II. DESCRIPTION OF ACTION

This chapter of the assessment provides a descriptive overview of Reclamation’s role on the lower Colorado River. Four specific areas are addressed: 1) an overview of the river and its operational facilities, 2) Reclamation’s discretionary role, acting on behalf of the Secretary, in implementing the Law of the River, 3) an overview of current river operation and maintenance activities employed by Reclamation to implement the Law of the River, 4) Reclamation activities under section 7(a)(1) of the ESA conserving threatened and endangered species, and 5) a summary.

Most of the lower Colorado River’s water, or about 96 percent of the annual supply, flows into the lower basin at Lees Ferry from the upper basin. The mean annual flow at Lees Ferry between 1935 and 1990 was about 10,165,000 acre-feet. The remaining 4 percent came from side flows during rainstorms and tributary rivers in the lower basin. Colorado River water flows are highly variable from year to year and the mean annual inflow is about 472,700 acre-feet. Figure 4 illustrates the quantities of lower Colorado River water released and diverted yearly.

The Law of the River requires the United States to operate the lower Colorado River with the following three main priorities: 1) for river regulation, improvement of navigation, and flood control, 2) for irrigation and domestic uses, including the satisfaction of present perfected rights, and 3) for power. Water cannot be released unless there is a valid beneficial use for the water, and it is then released at a time and in a way to meet the water delivery need, and to maximize other benefits including power production. Beyond these requirements, the United States takes into consideration such other needs on the river as recreation, wildlife, water quality, and species conservation. The facilities which were built to enable meeting these requirements are shown in Figure 5. More-detailed descriptions of these structures and others are provided in "Appendix D - Major Facilities on the lower Colorado River".

Hoover Dam is the northernmost Reclamation facility on the lower Colorado River and is located 68 miles downstream from Pierce Ferry. The dam provides flood control protection and the reservoir it forms provides the majority of the storage capacity for the lower basin. The dam’s four intake towers draw water from reservoir elevations above 895 feet and drive 17 generators within the dam’s powerplant. Maximum water flow rate through the generators is approximately 49,000 cubic feet per second (cfs). Lake Mead, the name of the reservoir behind Hoover Dam, can store 31,250,000 acre-feet of water up to an elevation of 1,221 feet at the top of the dam’s spillway gates. Lake Mead’s surface area is 162,700 acres when full. Water is diverted from, and some water is returned to, Lake Mead for use in southern Nevada for domestic purposes by the Southern Nevada Water Authority and other users.

Davis Dam is located 67 miles below Hoover Dam and operates as a re-regulation facility and powerplant. Lake Mohave behind Davis Dam can store up to 1,818,300 acre-feet of water at a maximum elevation of 647 feet. When full, Lake Mohave covers 28,500 acres and backs water 67 miles upstream to the tailrace, or the water outlet, of Hoover Dam. Water is released through Davis Dam’s five generators from lake elevations potentially as low as 570 feet, and the maximum efficient rate of flow through the generators is 28,000 cfs. Water is diverted and pumped from Lake Mohave for domestic uses. Typical water travel time from Hoover Dam to Davis Dam is 4 to 6 hours.

Parker Dam is located 88 miles downstream from Davis Dam and operates as a forebay and desilting basin for the Colorado River Aqueduct and the CAP. Lake Havasu behind Parker Dam has a storage capacity of 648,000 acre-feet of water at a maximum lake elevation of 450 feet. When full, Lake Havasu backs water up-river for 45 miles and covers 20,400 acres. Lake Havasu is limited in its elevation and has only a 10-foot operational range between elevations 440 to 450 feet. Water above 400 feet in elevation is diverted through the powerplant’s four generators with a maximum efficient flow rate of 19,000 cfs. Water diverted from the lake is delivered by The Metropolitan Water District of Southern California (MWD) through its Colorado River Aqueduct to southern California and through the Granite Reef Aqueduct by the Central Arizona Water Conservation District (CAWCD) to central Arizona. Water is also diverted and pumped above Parker Dam for domestic, irrigation, and environmental uses. Typical water travel time from Davis Dam to Parker Dam is just over 1 to 1.5 days.

Headgate Rock Dam is located 14 miles downstream from Parker Dam and was constructed in 1942 for the Bureau of Indian Affairs as a diversion facility for the Colorado River Indian Tribes (CRIT) Reservation. The dam was recently retrofitted to provide power generation capability. Lake Moovalya behind the dam has limited water storage capacity and is occasionally drained during the winter for diversion-canal maintenance. The maximum elevation of Lake Moovalya is 364 feet and backs water up for 10 miles. Water from a maximum depth of 15 feet is released though several generators with a combined flow rate of 20,000 cfs. Water is diverted by gravity immediately behind the dam though the CRIT canal for use on the CRIT reservation. Water is also diverted and pumped from Lake Moovalya for domestic, irrigation, and environmental uses. Typical water travel time from Parker Dam to Headgate Rock Dam is 1 to 4 hours.

Palo Verde Diversion Dam is located 44 miles downstream of Headgate Rock Dam and was constructed between 1956 and 1957 as a diversion dam to replace and improve the reliability of the Palo Verde Irrigation District’s (PVID) original gravity diversion facilities. Storing water to a maximum 46-foot depth, the dam has no effective water storage or flood control capability. Water is diverted by gravity immediately above the dam though the PVID canal. The canal can transport a maximum flow of 1,800 cfs. Water also is diverted and pumped above Palo Verde Diversion Dam for domestic, irrigation, and environmental uses. Typical water travel time from Headgate Rock Dam to Palo Verde Diversion Dam is about 1 day.

Senator Wash Dam and Reservoir is located 85 miles downstream from Palo Verde Diversion Dam and 2 miles upstream from Imperial Dam. The purpose of this off-stream pump-storage facility is to improve water delivery reliability and to reduce waste of Colorado River water when water orders change or precipitation causes side-channel inflow. The facility allows Reclamation to capture and store water not needed for delivery below Parker Dam or to release water if demands are greater than the existing river supply.

Imperial Dam is located 90 miles downstream of Palo Verde Diversion Dam or 147 miles downstream of Parker Dam (the last storage or regulation facility). Imperial Dam was built between 1936 to 1940 as a gravity diversion facility for the All-American Canal, to replace the original Alamo Canal, and as a diversion facility for the Gila Gravity Main Canal. Imperial Dam has no effective storage or flood control capability and stores water to a maximum depth of 23 feet. Water is released though the dam though the sluiceway gates. The All-American Canal can transport a maximum water flow of 15,155 cfs and supplies water to the Imperial Irrigation District (IID), the Coachella Valley Water District (CVWD), and other small users. The Gila Gravity Main Canal can transport up to 2,200 cfs and supplies water to the Wellton-Mohawk Irrigation and Drainage District (WMIDD) and to the Yuma area. Water also is diverted and pumped between Palo Verde Diversion Dam and Imperial Dam for domestic, irrigation, and environmental uses. Typical water travel time from Palo Verde Diversion Dam to Imperial Dam is about 2 days.

Laguna Dam is located 5 miles downstream of Imperial Dam and was constructed between 1905 and 1909 as part of the Yuma Project to provide for gravity diversion of Colorado River water. However, with the construction of Imperial Dam immediately upstream, the Yuma Project was reconfigured in June 1948 to use Imperial Dam for the Gila Gravity Canal diversion. The dam creates Mittry Lake and impounds water to a depth of 10 feet at a surface elevation of 154 feet. Today Laguna Dam serves as a regulating structure for sluicing flows controlling downstream sediment and helps meet Mexico’s water delivery orders. Typical water travel time from Imperial Dam to Laguna Dam is about 2 hours.

Morelos Dam is located 22 miles downstream of Laguna Dam and is the primary Colorado River water diversion facility for Mexico. The water is transported into the Alamo Canal for use in Mexico. The dam has no effective storage or flood control capacity. Morelos Dam was built, and is operated and maintained, by Mexico. Typical water travel time from Laguna Dam to Morelos Dam is about 6 hours.

The Limitrophe Division is the 22-mile reach of the river that borders Mexico and extends from Morelos Dam to the SIB near San Luis, Arizona. The division is essentially dry during normal years due to the diversion of water by Mexico at Morelos Dam.

This section presents a condensed description of those activities of the Secretary, acting either directly or through Reclamation, undertaken in the operation and maintenance of the lower Colorado River and its reservoirs. This information is provided to establish an understanding of those activities and to provide a basis for an informed biological opinion determination on the effects of the appropriate operational and maintenance activities on the lower Colorado River system.

In accordance with the ESA and the attendant FWS CFR regulations, and for the purpose of establishing the action under consultation, this subsection specifically identifies future Reclamation activities which are discretionary and differentiates as non-discretionary those activities mandated by law, Court decrees, settlement acts, codified regulations, contracts, or other legal requirements.

The following discussions differentiate between the Secretary’s discretionary and non-discretionary authority for each of the major actions addressed by this BA. Conservation measures under section 7(a)(1) of the ESA have been described as discretionary.

The Boulder Canyon Project Act of 1928 (December 21, 1928, 45 Stat. 1057; 43 U.S.C. § 617) and the Flood Control Act of 1944 (December 22, 1944, 58 Stat. 890; 33 U.S.C. § 709) provided for flood control activities in the lower Colorado River. Flood control operations have the first priority on the lower Colorado River as mandated by the Boulder Canyon Project Act.

Section 2(b) of the Boulder Canyon Project Act allocated funds for flood control for the construction of Hoover Dam. Subsequently, section 7 of the Flood Control Act of 1944 established that the Secretary of War (now the Army Corps of Engineers [COE]) will prescribe regulations for flood control for projects authorized, wholly or in part, for such purposes.

The Los Angeles District of the COE published the current flood control regulations in the "Water Control Manual for Flood Control Hoover Dam and Lake Mead Colorado River, Nevada and Arizona" dated December 1982. The Field Working Agreement between the COE and Reclamation for the flood control operation of Hoover Dam and Lake Mead, as prescribed by the manual, was signed on February 8, 1984, and is included as Appendix H of this BA. The next review and possible revision of the flood control manual will occur within the next 5 years. Reclamation cannot predict the content of that review or the product thereof; thus those biological impacts will be addressed separately from this document.

The process of establishing the flood control regulations encompasses an analysis of the facts and the application of the best available technology. Within that framework, the COE must weigh and balance the various factors and has the responsibility for any discretionary decisions resulting in the flood control regulations. The COE conducts oversight activities when Hoover Dam is in flood operations. The Secretary has no discretion in making the minimum flood control releases from Lake Mead through Hoover Dam during flood control operations. When the required minimum flood control releases are less than the required releases for downstream water uses, the additional increment released to meet those uses is released by the Secretary in his role as Watermaster.

An analysis of the "Water Control Manual for Flood Control Hoover Dam and Lake Mead Colorado River, Nevada and Arizona" reveals that of the various triggers for releases studied in the preparation of the manual, very little difference was identified in the river flows under the different scenarios, except in extreme and rare events. The major effects occurred in upper basin storage, with resultant changes in the probability of a system drought.

A description of the operation process for flood control for Hoover Dam is presented in part C.1.entitled "Flood Control" of this document.

The COE is not responsible for the flood control criteria related to Davis Dam and Parker Dam, although the respective lake elevations and the operation of Davis Dam and Parker Dam are affected and, in part, determined by the flood control releases from Hoover Dam. The decision to include flood control as an operational parameter and the operation of the flood control aspects of Davis and Parker Dams fall within the Secretary’s discretion. In another sense, the inclusion of the flood control aspects of Davis and Parker Dams is prescribed in the Law of the River, for the waters entering the system via tributary runoff become mainstream water, and the release of these waters is subject to the requirements and prohibitions placed upon the Court decree further described in this section. The discretionary component of operational water elevation levels of Davis Dam and Parker Dam, which reflect flood control as one of the parameters and as prescribed by Reclamation for Davis Dam and Parker Dam, are shown in Figures 15 (Lake Havasu Operational Constraints) and 17 (Lake Mohave Operational Constraints) and are within the scope of this consultation.

Over the past 74 years, the upper and lower basins and the associated body of laws, Court decrees, regulations, and contracts have developed into two very different bodies of law for the upper and lower basins. The following synopsis establishes the authority and operational framework of the Secretary in the operation of the lower Colorado River basin. Reclamation serves as the representative of the Secretary in the implementation of these responsibilities.

The Colorado River Compact of 1922 divided the Colorado River into an upper and lower Basin, and Article III(a) provided 7.5 maf of water to the lower basin States. Article III(b) gave the lower basin right to increase its beneficial consumptive use of water by 1 maf per year. Article III(c) requires that the burden of any deficiency in meeting international commitments for supplying Colorado River water to Mexico shall be borne equally between the upper basin and lower basin. Article III(d) requires that the upper basin States will not cause the flow of the river at Lees Ferry to be depleted below an aggregate of 75 maf for any 10 consecutive years. Article III(e) states that water will not be withheld by the upper basin States or delivery required by the lower basin States, that cannot reasonably be applied to domestic and agricultural uses.

The Boulder Canyon Project Act of 1928 federalized the lower basin and established the Secretary as the Watermaster. The act made a mainstream basic apportionment of 7.5 maf to the three lower Division States in the following manner: Arizona 2.8 maf, California 4.4 maf, and Nevada 300,000 acre-feet of consumptive use per year. The act requires that all of the entitlements to Colorado River water existing as of the effective date of the act be met prior to anyone else receiving any additional Colorado River water. It requires that all parties using Colorado River water shall have a contract with the Secretary for the use of Colorado River water and the contract term shall be for permanent service. The Secretary is prohibited from releasing any Colorado River water unless the water is scheduled by an entitlement holder for beneficial use or the water is released for flood control releases. Section 13(a) approved the 1922 Compact,and Section 16 requires the Secretary to consult with the States.

The Mexican Water Treaty of 1944 (between the United States of America and the United States of Mexico) further defined the apportionment of Colorado River water.

The United States Supreme Court Decrees in Arizona vs. California, et al., of 1964, 1979, 1984.

The 1964 Decree, in Article II, states "The United States, its officers, attorneys, agents and employees are hereby severally enjoined:

"(A) From operating regulatory structures controlled by the United States and from releasing water controlled by the United States other than in accordance with the following order of priority:

"(B) From releasing water controlled by the United States for irrigation and domestic use in the States of Arizona, California and Nevada, except as follows:

Therefore, based on the Law of the River, entitlements to the beneficial use of Colorado River water in the lower basin have been established in the following four ways.

1. Court decrees for 4,156,847 acre-feet which includes the water rights perfected by the States and which existed prior to the effective date of the Boulder Canyon Project, Indian Reservations water entitlements, and other Federal entitlements listed in the Court decrees.

2. Secretarial reservations for Federal uses, such as the Bureau of Land Management (BLM), FWS, and Reclamation.

3. Contractual entitlements under section 5 of the Boulder Canyon Project Act.

4. The International Treaty with Mexico for 1.5 maf.

The Secretary is responsible for managing the lower basin and for providing for the delivery of Colorado River water entitlements to entitlement holders. A water delivery contract with the Secretary secures and protects the entitlement holder as the contract quantifies the amount of Colorado River water the entitlement holder is entitled to beneficially use and states the priority of that water use.

Secretarial determinations are based upon the decision whether conditions meet a "normal year," "surplus year," or "shortage year" as prescribed by the associated law and requirements. For the purposes of this document, a normal year is when the Secretary determines that there is sufficient mainstream water to satisfy the annual pumping and releases from Lake Mead to satisfy 7.5 maf of annual consumptive use in the lower basin, plus 1.5 maf for Mexico. A surplus year is when the Secretary determines that there is more water available than in a normal year, and a shortage year is when the Secretary determines that there is less water available than in a normal year. When an entitlement holder schedules water in a normal year or surplus year, the Secretary has no option but to deliver the water as prescribed by law and contract in the amounts and at the times requested, so long as it does not exceed that reasonably required for beneficial consumptive use. In a shortage year, the Secretary is required to consult with the affected parties and then factor in the shortages as prescribed by law and contract. These actions may be perceived to be discretionary, but, as required by law, there is a process of consultation based on water conditions. To date, a surplus has not been declared: however, within the next 5 years such a declaration is possible.

The Secretary is required by Article V of the Supreme Court decree to keep a record of all Colorado River water diversions, returns, and consumptive use, along with other water-related data, and to make that information available to interested parties at least annually. The water accounting function is non discretionary; whereas, the method or process utilized to collect and publish the report may be discretionary.

Typically, water schedules are placed by entitlement holders in advance. Some water schedules are placed a month in advance and call for daily, and sometimes hourly, water volumes. The advance schedules may be revised or changed at the request of the entitlement holder. Since water entitlement contracts are for perpetuity, the water schedule terms and conditions may vary due to the effective date of the contract. Some of the contracts have a maximum rate of diversion in terms of cfs, approved points of diversion(s), and authorized type of water use or place of water use. The Secretary adopted the 1931 California Seven Party Agreement for 5,362,000 acre-feet of water and entered into a master contract with the State of Nevada in 1942 for 300,000 acre-feet of water and with the State of Arizona in 1944 for the 2,800,000 acre-feet of water. These actions effectively allocated 8,462,000 acre-feet of the lower Colorado River basin’s water for use in the United States by 1944. A detailed description of the process for handling water orders is presented below in part C.1.d..

The level of Secretarial discretion, if any, related to a water entitlement is directly related to the type of entitlement. For example, the Supreme Court-decreed entitlements with the five Indian Tribes, FWS, and the National Park Service (NPS) have never been incorporated into administrative agreements or contracts. In fact, as long as the water is used at the decreed place of use and those entitlement holders do not request a change or a new benefit, the Secretary has extremely limited control over these entitlements. Other present perfected right entitlement holders, as listed in the Supreme Court decree, may or may not have an administrative agreement (contract) with the Secretary; the terms and conditions of such a contract for present perfected rights are few.

Therefore, the amount of control or discretion the Secretary has over any one entitlement ranges from very limited to extremely limited, varies by the type of the entitlement, and depends upon the execution date of the contract and its associated terms and conditions. Secretarial actions must not conflict with the contract terms or the mandates of the Court decree from which the Secretary is severally enjoined.

The Secretary may have limited discretion over such conditions as non-use, non beneficial use, or water conservation. However, the Secretary has no effective meaningful discretion over meeting an entitlement holder’s valid request for water for beneficial use. This holds true for a municipality, irrigation district, Indian Tribe, or wildlife refuge. The Secretary may have limited flexibility regarding when water is released from Lake Mead, based on a minor amount of storage capacity in the downstream reservoirs for re-regulation.

The Regional Director of Reclamation’s Lower Colorado Region, on behalf of the Secretary in his Watermaster role, may make annual determinations relating to water conservation measures and delivery, distribution, and use of Colorado River water pursuant to 43 CFR Part 417. Deliveries of Colorado River water will not exceed those reasonably required for beneficial use.

The following actions are discretionary:

The discretionary actions associated with the use of Colorado River water relate to non-consumptive water uses for which Reclamation is not severally enjoined. For example, such non-consumptive uses could include, recreation on the reservoirs and the Colorado River, increased flushing flows at Topock Marsh, and fish habitat within or adjacent to the mainstream of the Colorado River (such as Three-Fingers Lake). If any of the activities would have a consumptive use, the party responsible for the use would have to acquire a water entitlement to account for the water consumptively used as required by the Court decree.

It should be noted that the restrictions and obligations in the laws and decrees are so encompassing that the Senator Wash re-regulating reservoir was authorized and constructed to help meet the mandatory requirements for water delivery. Similarly, the storage and resultant elevations of Lake Mohave and Lake Havasu are used to re-regulate the local storm waters and last minute changes in water orders. These re-regulations are minuscule compared to the river’s total flow and are therefore unmeasurable. However, within very narrow confines, the management of the lake levels of these three facilities may be considered discretionary.

On average, 96 percent of the water in the lower basin enters the system at Lee Ferry, and the remaining 4 percent comes from side flows into the system from the rivers or occasional rain flows. According to the Law of the River, this remaining 4 percent becomes Colorado River mainstream water when commingled with the Colorado River or its associated underground water aquifer and is subject to the same restraints.

The Secretary’s role in the lower Colorado River basin, regarding water storage and the delivery of water apportionments and entitlements throughout the system, is subject to the Law of the River which includes the 1922 Compact, the Boulder Canyon Project Act, the 1964 Supreme Court decree, and contracts, settlement decrees, and applicable Federal and State law.

The Secretary, under the powers vested by Congress in Section 5 of the Boulder Canyon Project Act, as confirmed by Section II(B)(2) of the 1964 Decree, has certain discretionary authority to determine when more than 7.5 maf of Colorado River water is available for consumptive use during a calendar year in the three lower Division States; this is a surplus determination. When making this determination, the Secretary must consider all relevant factors as specified in Section III(3)(b) of the long-range operating criteria, including, but not limited to, the following conditions.

Pursuant to the decree, water in excess of 7.5 maf consumptive use is apportioned 50 percent to California, 46 percent to Arizona, and 4 percent to Nevada. If a State will not use all of its apportioned water for the year, the Secretary may allow the other States to use the unused apportionment in that year, as outlined in Section II(B)(6) of the Court decree. Unused apportionment means Colorado River water within a lower basin State’s basic or surplus apportionment, or both, which is not put to beneficial consumptive use in that year within that State. The decree in Section II(B)(6) specifically says that a right to the recurrent use of unused apportionment cannot accrue by reason of the use thereof. The unused apportionment water can be used when declared available by the Secretary; the use must be provided for by a contract with the Secretary and must be considered a beneficial use. Unused apportionment water may be withdrawn, subject to a 30-day written notice.

The Secretary also has the discretion to determine if the system conditions warrant supplying less than 7.5 maf for consumptive use, referred to as a shortage; a shortage has never been declared and is not expected within the next 5 years.

The minimum and maximum water flow rates (average monthly flow rates in cfs) at the NIB are the sum of the minimum and maximum flow rates specified in the Mexican Water Treaty of 1944:

The annual delivery at the NIB is approximately 1,360,000 acre-feet annually (Minute 242). The minimum and maximum water flow rates in cfs and the corresponding acre-feet for delivery to Mexico at the NIB are shown in Table 3.

Table 3. Minimum and maximum flow rates for the delivery of water to Mexico at the NIB

Month

Minimum

(cfs and acre-feet)

Maximum

(cfs and acre-feet)

January

900 / 55,340

5,500 / 338,187

February

900 / 49,984

5,500 / 305,459

March

1,500 / 92,233

5,500 / 338,187

April

1,500 / 89,258

5,500 / 327,278

May

1,500 / 92,233

5,500 / 338,187

June

1,500 / 89,258

5,500 / 327,278

July

1,500 / 92,233

5,500 / 338,187

August

1,500 / 92,233

5,500 / 338,187

September

1,500 / 89,258

5,500 / 327,278

October

900 / 55,340

5,500 / 338,187

November

900 / 55,546

5,500 / 327,278

December

900 / 55,340

5,500 / 338,187

The flow rate for the delivery of Colorado River water at the land boundary near San Luis is discussed in the Mexican Water Treaty of 1944. Article 15, Schedule I of the treaty states in part:

Article 15, Schedule II, paragraph B of the treaty states in part:

Each of the major lower Colorado River hydroelectric facilities have legislative authorization for the production of electric power. Reclamation is the Federal agency authorized to produce this power. Water is released from Hoover Dam (approximate elevation 1,200 feet above mean sea level [msl]) through a combination of the 19 dedicated generator pipes into Lake Mohave (approximately 640 feet in elevation). Water is then released through Davis Dam through a combination of the five dedicated generator pipes into Lake Havasu (approximate elevation 448 feet). Since Parker Dam is the last major United States-owned, Reclamation-administered hydroelectric facility on the lower Colorado River and there is no other significant downstream storage, all releases scheduled from Parker Dam are in response to downstream water orders or reservoir regulation requirements.

Although Reclamation is the Federal agency authorized to produce this power, Western Area Power Administration (WAPA or Western) is the Federal agency authorized to market this power. WAPA enters into electric service contracts on behalf of the United States with private and municipal entities.

The topic of power operations in the lower basin must be prefaced with a discussion of the authorizing legislation for the DOE under Public Law 95-91 dated August 4, 1977. Section 302 of this law is entitled "Transfers from the Department of the Interior." Section 302(a)(1)(E) transferred from the Secretary of the Interior to the Secretary of Energy the following functions:

"(E) the power marketing functions of the Bureau of Reclamation, including the construction, operation, and maintenance of transmission lines and attendant facilities;"

This is the legislative authority for the creation of WAPA. WAPA entered into a Joint Operating Agreement (JOA) with Reclamation’s Lower Colorado Region dated February 8, 1980, to implement section 302(a)(1)(E) of Public Law 95-91. At the time, Reclamation was known as the Water and Power Resources Service (Service). The "System Operations" section of the JOA states in pertinent part:

This means that Reclamation is obligated to meet the Hoover, Parker, and Davis Dams’ power generation schedules which are produced by WAPA in accordance with existing electric service contracts, subject to water availability. The released water generates power, but water is not released for the sole purpose of generating power. Even though the Parker-Davis electric service contracts were not signed by Reclamation representatives, the contractual obligations with respect to generation scheduling are Federal obligations, and Reclamation must adhere to WAPA's generation schedules as WAPA must produce these schedules in accordance with the electric service contracts. Reclamation does have the discretion to ask the electric service customers to renegotiate their contracts [ If the United States is relieved of the electric service contractual obligations, then the United States could be responsible for direct financial reimbursement to the electric service contractors.] .

The General section of the JOA states in pertinent part: "Changes to the agreement and the appendices will be effected through Service's Regional Office and Western's Area Office." Any change to the JOA would have to be agreed upon by these two offices.

Parker and Davis Dams and Powerplants:

The authorizing legislation of these facilities required the generation of power and granted exclusive rights of the facility power capacity and energy to priority use power customers. "Capacity" in this usage means the electrical generating capacity of on-line generator units, whether or not they are actually producing power at any specific time. The capacity and energy utilized by the Parker-Davis electric service customers is termed "firm electric service power." The users have firm capacity and firm energy contracts with the United States which are in effect until midnight, mountain standard time, September 30, 2008. These contracts were signed by the Area Manager of WAPA’s Boulder City Area Office (now known as the Regional Manager of Western’s Desert Southwest Region). The Parker-Davis electric service contracts stipulate contract rates of delivery (CROD) for each firm electric service customer. The CROD for a contractor specifies the maximum number of whole or partial units that must be available to supply power to that customer at their specific point of power delivery. For example, if a specific hypothetical power customer had a Parker CROD of 30 megawatts (MW), it would be entitled to the output of three-quarters of a Parker generating unit (one whole Parker generator is 40MW) at any time during the applicable season (summer or winter) delivered to the contract-specified point of power delivery. There are contractual minimum summer CROD and winter CROD. The higher the seasonal CROD, the more electric generator units must be operated concurrently at the associated facility.

Each Parker-Davis electric service contract contains essentially the same language. As an example, subsection 5.1 of Contract No. 87-BCA-10108 with Yuma Irrigation District is entitled "Western’s Energy and Capacity Obligations." Paragraph 5.1.1 of that subsection states in pertinent part: "The Contract Rate of Delivery will be available in any hour within the billing period." This means that if the "firm" electric service customer requests a capacity within its minimum seasonal CROD, at any hour, and water is on order to supply that capacity, the United States is obliged to make the power resource available (that is, put the generator units on-line and release the water through them).

MWD is a water and power utility service district which serves a significant portion of southern California. MWD is a recognized utility monopoly regulated by the State of California and has a perpetual contract right to 50 percent of electric power generated at Parker Dam.

Reclamation has the discretion to ask the Secretary of Energy to ask the electric service customers to renegotiate their contracts. Presently, the funding source for operation, maintenance, and replacement (OM&R) for the dams and powerplants and for WAPA’s associated marketing expenses is supplied through Federal appropriations. These appropriations are then repaid to the Federal Treasury from power sale revenues. Beginning in fiscal year 1998, there will be an administrative modification to this system; Federal funds will no longer be made available for this purpose. Instead, the power contractors will provide funding at the beginning of each fiscal year to cover OM&R and WAPA’s marketing expenses. This expense will be repaid throughout the fiscal year by power customers receiving credits on their power supply statements.

Hoover Dam (Boulder Canyon Project):

Each electric service contract for Hoover Powerplant electric service was executed on behalf of the United States by WAPA. Reclamation has signed in concurrence.

Subparagraph 5.1.2.2 in each contract states in part:

The limitation referenced in paragraph 5.6.2 deals with powerplant equipment emergencies. Reclamation has concurred with this subparagraph.

The use of a "dynamic signal" means that each contractor can request its contractual power entitlement on a 4-second interval, which is the industry standard time step required by the Western Systems Coordination Council (WSCC). Reclamation is a fully participatory WSCC member and is obligated to follow the guidelines declared by the WSCC.

43 CFR Part 431:

The "General Regulations for Power Generation, Operation, Maintenance, and Replacement at the Boulder Canyon Project, Arizona/Nevada," are provided in 43 CFR Part 431. Although Reclamation cannot violate this or any CFR, such CFR’s are subject to revision. The following authorities provided the legal basis for 43 CFR Part 431:

The following definitions are included in § 431.3:

The operational requirements needed to satisfy 43 CFR Part 431 is non-discretionary.

Power generation responsibilities are discussed in § 431.4, which states in pertinent part:

The administration and management of the Colorado River Dam Fund is found in § 431.7, which states in pertinent part:

Since these receipts are the major source of funding for the operation and maintenance of the Boulder Canyon Project, the operational requirements needed to generate these receipts and revenues are non-discretionary.

The Hoover Power Plant Act of 1984:

Section 106 of this act authorized the reimbursement of funds advanced by non-Federal purchasers for the uprating program as a repayment requirement of the Boulder Canyon Project. The non-Federal entities provided the United States with $165 million in up-front funding to implement a major construction program to increase generation capacity at Hoover Powerplant. The methodology for the repayment of the funds is described in 10 CFR Part 904.12 which reads:

"(a) Funds advanced to the Secretary for the Uprating Program and costs reasonably incurred by the Contractor in advancing such funds, as approved by Western, shall be returned to the Contractor advancing the funds during the contract period through credits on that contractor’s power bills. Appropriate credits will be developed and applied pursuant to the terms and conditions agreed to by contract or agreement.

"(b) All other obligations of the United States to return funds to a Contractor shall be repaid to such Contractor through credits on power bills, with or without interest, pursuant to terms and conditions agreed to by contract or agreement."

This act requires the United States to use electric service credits paid over a 50-year period to repay the $165 million in up-front funds provided by the power contractors. The additional generating capacity provided by these funds would need to be optimized to produce the revenue required to repay this obligation.

The Colorado River Front Work and Levee System (CRFWLS) Act of 1946 (as amended) provides that for the purposes of controlling the floods, improving navigation, and improving the flow of the Colorado River, Reclamation will (i) operate and maintain the CRFWLS in Arizona, Nevada and California, (ii) construct, improve, extend, operate and maintain protection and drainage works and systems, (iii) control said river, and improve, modify, straighten, and rectify the channel thereof, and (iv) conduct investigations and studies in connection therewith.

Although these directions and responsibilities are relatively explicit as to what must be done, the details of the works, and the "how" and "when" parameters, are left to the discretion of the Secretary and Reclamation. The channel maintenance and levee system processes are considered discretionary for the Secretary and are covered within this assessment and consultation.

The Yuma Desalting Plant (YDP), completed in 1992 and located about 6 miles west of Yuma, Arizona, was constructed to enable the United States to comply with its water quality obligations under Minute No. 242, an extension of the 1944 Treaty with Mexico. Non-discretionary operation of the YDP to meet the salinity requirement of the water delivered to Mexico is not anticipated during the 5-year temporal scope of this assessment. Instead, this assessment addresses discretionary one-third operation of the YDP. Discretionary operation of the YDP at one-third capacity may occur to market approximately 26,200 acre-feet of the 110,000-132,000 acre feet of water currently discharged annually to the Cienega de Santa Clara (Cienega), a marsh complex located in Sonora, Mexico, near the Sea of Cortez.

The one-third operation is addressed programmatically in this assessment because a specific plan and agreement for marketing the desalinated water have not been completed at this time. An Environmental Impact Statement (EIS) was completed in 1975 for implementing Title I of the Salinity Control Act which includes the YDP. All mitigation measures identified during the development of the EIS have been completed. However, operation of the YDP for any purpose has international involvement and potential environmental impacts in Mexico. Therefore, startup and operation of the YDP for water marketing will be negotiated with Mexico by IBWC, the Federal agency responsible for ensuring that all treaties and agreements between the United States and Mexico are honored, including environmental agreements such as the North American Agreement on Environmental Cooperation.

The 5-mile zone is a 36,000-acre area 10 miles south of Yuma, Arizona, containing Reclamation-acquired and other lands needed to construct, operate, and maintain a well field providing water to Mexico in partial fulfillment of the 1944 Treaty with Mexico and as required by Title I of the Salinity Control Act. Reclamation’s discretionary activities in the zone are limited to maintaining the 21 wells in the well field, the associated delivery canal, and the YDP sludge disposal site.

Reclamation has discretion to conduct activities benefitting threatened and endangered species under section 7(a)(1) of the ESA. Under the Act, Reclamation and other Federal agencies are permitted to:

In addition to aiding the recovery of listed species, Reclamation’s endangered species program also has, as an objective, the conservation of non-listed species of concern to prevent their future listing.

Flood control was specified as a primary project purpose by the Boulder Canyon Project Act, the act authorizing Hoover Dam. The COE is responsible for developing the flood control operation plan for Hoover Dam and Lake Mead as indicated in 43 CFR 208.11. The plan is the result of a coordinated effort by the COE and Reclamation, but the COE is responsible for providing the flood control regulations and has authority for final approval. Any deviations from the flood control operating instructions must be authorized by the COE and the Secretary is responsible for operating Hoover Dam in accordance with these regulations. Flood control regulations for Lake Mead were established to deal with two distinct types of flooding: rain and snowmelt. Snowmelt constitutes about 70 percent of the annual runoff of the Colorado River into Lake Mead.

Lake Mead's uppermost 1.5 maf of storage capacity, between elevations 1219.6 and 1229.0, is allocated exclusively to control floods from rain events. Within this capacity allocation, 1.218 maf of flood storage is above elevation 1221.4, which is the top of the raised spillway gates.

Flood Control regulations specify that once flood releases exceed 40,000 cfs, the releases shall be maintained at the highest rate until the reservoir drops to elevation 1221.4 msl. Releases may then be gradually reduced to 40,000 cfs until the prescribed seasonal storage space is available.

The flood control regulations set forth two primary criteria to deal with snowmelt:

1) preparatory reservoir space requirements, and 2) application of runoff forecasts to determine releases.

In preparation for the coming year's season of snow accumulation and associated runoff, progressive expansion of total Colorado River system reservoir space is required during the latter half of each year. Minimum available flood control space increases from 1.5 maf on August 1 to 5.35 maf on January 1. Required flood storage space can be located within Lake Mead and in specified upstream projects: Lakes Powell and Navajo, and Blue Mesa, Flaming Gorge and Fontenelle Reservoirs. Minimum Lake Mead space required for exclusive flood control is 1.5 maf. The following chart shows the amount of required flood storage space by date:

Minimum Required System Space

Date

Amount in acre-feet

August 1

1,500,000

September 1

2,270,000

October 1

3,040,000

November 1

3,810,000

December 1

4,580,000

January 1

5,350,000

Normal space-building releases from Lake Mead to meet the required August 1 to January 1 flood control space are limited to a maximum of 28,000 cfs. Releases based on the water entitlement holders’ demand are much less than 28,000 cfs.

Between January 1 and July 31, flood releases, based on forecasted inflow, may be required to prevent filling of Lake Mead beyond its 1.5 maf minimum space. Starting on January 1, the Colorado River Forecasting Service issues runoff forecasts each month through July 31. The release schedule contained in the COE regulations is based on increasing releases in six steps (shown in the following chart):

Flood Control Releases at Hoover Dam

Step

Amount in cubic feet/second

Step 1

0

Step 2

19,000

Step 3

28,000

Step 4

35,000

Step 5

40,000

Step 6

73,000

The lowest step, zero cfs, corresponds to times when the regulations do not require flood control releases. Hoover Dam releases are then made on water and power objectives. The second step, 19,000 cfs, is based on the Powerplant capacity of Parker Dam. The next step, 28,000 cfs, is the approximate maximum release that will not cause damage through the Parker Strip and corresponds to the Davis Dam Powerplant capacity which is 28,000 cfs. The fourth step in the COE releases is 35,000 cfs, which corresponds to the Powerplant capacity of Hoover Dam in 1987. The present Powerplant capacity at Hoover Dam is 49,000 cfs. At the time Hoover Dam was completed, 40,000 cfs was the approximate maximum nondamaging flow downstream from the dam. In addition the "Colorado River Floodway Act" requires that the minimum flood release from Hoover Dam can be no less than 40,000 cfs plus tributary flows. Prior flood control plans regulated outflow to 40,000 cfs, which forms the fifth step. Releases of 40,000 cfs and greater would result from unusually large floods. The sixth and last step in the series, 73,000 cfs, is the maximum controlled release from Hoover Dam without spillway flow.

Runoff forecasts are received from the Colorado River Forecast Service in Salt Lake City, Utah. Flood control releases are required when forecasted inflow exceeds available storage space at Lakes Mead and Powell and allowable space in other upper basin reservoirs. This includes accounting for projected bank storage and evaporation losses at both lakes, plus net withdrawal from Lake Mead by the Southern Nevada Water Project. The COE regulations set the procedures for releasing the volume that cannot be impounded.

Average monthly releases are determined early in each month and apply only to the current month. The releases are progressively revised in response to updated runoff forecasts and changing reservoir storage levels during each subsequent month throughout the January 1 - July 31 runoff period. If the reservoirs are full, drawdown is accomplished to vacate flood control space as required. Unless flood control is necessary, Hoover Dam is operated to meet established downstream water requirements.

Lake Mead end-of-month elevations are driven by downstream demands, Glen Canyon releases, and Mexican Water Treaty deliveries to Mexico. Lake Mead end-of-month target elevations are not set as are Lake Mohave and Lake Havasu. Normally, Lake Mead elevations rise into March and decline with increasing irrigation deliveries through June or later and then begin to rise again. Lake Mead’s storage capacity provides for the majority of Colorado River regulation from Glen Canyon Dam to the border with Mexico.

Due to the amount of vacant storage in the Colorado River reservoirs, no flood control releases are anticipated in 1996. For purposes of providing insight into annual flood and drought cycles on the lower Colorado River, Figures 6 and 7 provide an historical summary of annual flows at Lees Ferry and below the Hoover Dam site, for the pre- and post-construction periods of Glen Canyon and Hoover Dams. For the same purpose, the yearly high and low water elevations for Lake Mead are illustrated in Figure 8.

Annual water deliveries may be reduced if a drought on the Colorado River system occurs. If a surplus year is declared on the Colorado River system, flows will be adjusted to meet water entitlement holders’ demands and to drain system storage.

Each year, Reclamation consults with the lower basin States, the Indian Tribes, and Colorado River water users regarding water conservation and the use of Colorado River water. Reclamation’s authority for such activities is found in section 602 of the Colorado River Basin Project Act of September 30, 1968. Reclamation also may review specific uses under 43 CFR 417 which provides the authority for Reclamation to conduct consultations with each public or private organization that is entitled to Colorado River water. Water users are contacted by Reclamation to discuss water needs and are requested to furnish monthly estimates for the upcoming year. The purposes of the consultations are to make annual recommendations relating to water conservation measures and operating practices in the use of Colorado River water and to determine if estimated water requirements for the next year will exceed reasonable beneficial use.

All of the information gathered is used to develop an Annual Operating Plan (AOP) as required by the Colorado River Basin Project Act, after taking into consideration probable runoff, depletions, and consumptive uses. The AOP is formulated for the upcoming year under a variety of possible conditions. The plan is developed based on projected requirements, existing storage conditions, and probable inflows. It is prepared by Reclamation, acting on behalf of the Secretary, in cooperation with the seven basin States, other Federal agencies, Indian Tribes, State and local agencies, and the general public, including environmental interests.

The AOP is designed to govern the general operation of the river system on a seasonal and annual basis and specifies, as an objective, the minimum amount of water to be released from Lake Powell through Glen Canyon Dam for the year. For the lower basin, the AOP determines whether demands will be met according to shortage, surplus, or normal water year supply conditions. A forecast of water supply, reported water use to date, and projected water use for the year is produced monthly as the information becomes available to Reclamation. The 24-month study, discussed later in this section, provides the monthly updates and projected reservoir conditions throughout the lower basin for the following 2 years.

Prior to the beginning of the calendar year, diversion schedules are requested from water users entitled to Colorado River water. These schedules are of estimated monthly diversions, which allows Reclamation to determine a tentative schedule of monthly releases through the Hoover Powerplant. Actual monthly releases are determined by the demand for water downstream of Hoover Dam. Daily changes in water orders are made to accommodate emergencies, rainstorms, changes in wind, holidays, and various other parameters. Appendix E provides additional information on reservoir releases and elevations for non-flood release years during 1980-1995 and projected releases from 1996-2010.

The scheduling and subsequent release of water through Davis and Parker Dams effect daily fluctuations (going through its changes in a day, a day being 24 hours) in river flows, depths, and water surface elevations downstream of these structures. Since such releases may affect downstream critical habitat reaches, typical seasonal flow patterns are illustrated for representative gauging locations on the lower Colorado River (Figures 9,10,11,12,13). The location of the representative gauging stations are shown on Figure 2a and their names and distance (in miles) from the SIB are: Davis Dam, 275.4; Parker Dam, 192.2; Water Wheel, 152; Taylor Ferry, 106.6; and below Cibola Valley, 87.3. Typical seasonal flows (in cfs) and water surface elevations (in feet msl) are shown for each of the five stations. Variations in water depths are illustrated for representative stations in Appendix E.

Figures 9 and 10 demonstrate that the water surface elevation fluctuates most noticeably in the river reaches closest to the dams. Those fluctuations become more and more attenuated as the distance downstream increases, as shown in Figures 12 and 13. The Mohave Valley and Parker Divisions of the river are most affected by fluctuations on a daily basis. The Imperial, Laguna and Yuma Divisions are the least affected. The river fluctuates seasonally with the highest water levels occurring during the summer and the lowest water levels occurring during the late fall and winter, except during flood releases. The current ecosystem on the river is, in part, a result of these daily and seasonal fluctuations.

Under normal operating conditions, Reclamation’s Yuma Area Office (YAO) receives daily water orders for those water entitlement holders within the United States and Mexico below Parker Dam. Water orders are totaled and submitted to Hoover Dam personnel who then coordinate releases to meet downstream water demand and power demands from Parker, Davis, and Hoover Dams.

Mexico submits each Wednesday a daily water order, to cover the following week, through IBWC at Yuma; however, Mexico cannot change its daily water order once it is received, except in the case of an emergency. United States water entitlement holders below Parker Dam also furnish their water orders to YAO each Wednesday; however, United States water entitlement holders may modify their master schedule of water orders at least 3 days in advance of water releases from Parker Dam, and they may also vary from their master schedule on a daily basis if necessary. Release requirements from Parker Dam are equal to the water required by Mexico and United States users downstream of Parker Dam and system losses resulting from transporting the water from Parker Dam to Imperial Dam.

When either more or less water than needed by United States entitlement holders arrives at Imperial Dam, storage behind Imperial Dam, Laguna Dam, and Senator Wash Dam is utilized to attempt to regulate incoming Colorado River flows in order to meet actual water demand and prevent over deliveries of water to Mexico. Regulating flows involve either pumping water into storage if more water arrives than is demanded or releasing water into the river when there is not enough to meet demands. Changes to water demand may result from a change in weather (rainfall, frost warnings, wind, high temperatures, cooler temperatures, etc.), holidays, or structural failure of an irrigation facility.

Normal operational variances in elevation at Imperial Dam are from 180 feet to 180.9 feet msl. The top of the spillway at Imperial Dam is approximately 181 feet; this elevation is seldom exceeded. If water demand exceeds flows arriving at Imperial Dam for extended periods, the elevation behind Imperial Dam may, on very rare occasions (1 to 3 times per year), be drawn down to elevation 178.5 feet. This elevation would not be maintained for more than a few days. Elevations of the reservoir above Imperial Dam continuously fluctuate, to some degree, daily and during the day. Fluctuations are due to variability in the flows arriving at the dam and water entitlement holders’ demand changes.

Normal operational variances in elevation at Laguna Dam are from 138 feet to 151.3 feet msl. The top of the spillway at Laguna Dam is elevation 151.3 feet msl. The maximum elevation is met a few times a year when the storage is used to prevent or reduce over deliveries to Mexico. The lower elevations occur when it is necessary to use the water stored in Laguna Reservoir to meet Mexico's water order. This normally occurs when water demand has increased after releases have already been made from Parker Dam. Elevations behind Laguna Dam continuously change due to the continuously changing water demand at Imperial Dam.

Normal operational variances in elevation at Senator Wash reservoir are from 210 feet to 240 feet msl. The reservoir is currently on an elevation restriction at 240 feet msl for safety concerns regarding seepage above that level. Prior to the elevation restriction of 240 feet msl, the normal range in elevation was from 210 feet to 251 feet msl (the top of the spillway). Several potential repairs for Senator Wash which could allow full utilization of its storage capacity are under current review, but it will be a number of years before repairs can be accomplished. The reservoir elevation is continually fluctuating because Senator Wash is used to regulate flows arriving at Imperial Dam.

Flows arriving at Imperial Dam normally range from a high of about 14,400 cfs (which usually occurs in late spring to summer) to a low of about 2,500 cfs (which usually only occurs after a heavy local rainfall over the entire area below Imperial Dam, usually November or December, and when water entitlement holders are not taking water). Mexico's water order has to be delivered regardless of excess rainfall.

Flows below Laguna Dam usually range between 300 and 500 cfs. Occasionally flows may range up to 4,000 cfs or higher if a heavy rainfall has occurred.

Flows below Imperial Dam into the Colorado River Channel (California Sluiceway) normally range from about 250 cfs to about 350 cfs and are made up principally of return flows from the All-American desilting basins and gate leakage from the California sluiceway gates at Imperial Dam.

Sluicing flows are released to remove sediment accumulated from the desilting basins in the sluiceway channel. These sluicing flows usually occur 2 to 3 times a month and consist of flows ranging from 8,000 to 10,000 cfs which are released for periods of about 20 minutes. These flows carry sediment to the Laguna Desilting Basin located about 2 miles downstream from Imperial Dam.

Mexico is entitled to receive a total of 1.5 maf of water delivered at the NIB and SIB each year - of which at least 1.36 maf are to bedelivered via the Colorado River (normally consisting of releases from Colorado River system storage and drainage returns) to the NIB; up to 140,000 acre-feet of Colorado River water (normally consisting of drainage returns and wasteway flows) can be delivered at the SIB. In the event a surplus year is declared by the Secretary, Mexico may increase its annual water order by 200,000 acre-feet to a total of 1.7 maf. In the event of a declared shortage, water deliveries to Mexico would be reduced in the same proportion as consumptive uses in the United States are reduced.

In December of each year, Mexico provides the United States with an advance monthly water order for the following year. This water order can only be changed by providing the United States 30 days’ advance notice, and each monthly water order can be increased or decreased by no more than 20 percent of the original monthly water order. The treaty further stipulates that Mexico's total water order must be no less than 900 cfs and no more than 5,500 cfs during the months of January, February, October, November, and December. During the remainder of the year, Mexico's water order must be no less than 1,500 cfs and no more than 5,500 cfs. Daily water orders are usually not allowed to increase or decrease by more than 500 cfs.

Minute 242 defines the salinity requirements of Colorado River water delivered to Mexico. A salinity monitoring program is conducted at points below Parker Dam to the NIB. Computations are made projecting the annual salinity requirements from these data. If necessary, actions are taken to reduce salinity, such as reducing drainage pumping, or operating the YDP. Operating the YDP for salinity control is not expected to occur within the next 5 years.

The daily and hourly water release target process is set by collecting data in the reaches between Hoover, Davis, and Parker Powerplants as well as the SIB. The availability of water is determined by the 24-month study which is updated on a monthly basis. The 24-month study is compiled from present snow pack water content, reservoir storage, projections from water users for the current year and projections from historical data forecasting. The availability of generating units to deliver the required downstream flows is coordinated with the projected 24-month study and the 18-month unit outage estimate. The 18-month estimated individual unit maintenance schedule incorporates monthly water delivery needs, the contractual requirement of WAPA’s electric service customers, and required generator maintenance work. The annual 18-month unit outage schedule is updated on a monthly basis if changes are required.

The first reach from the SIB extends up river to Parker Dam, located at Parker, California, and is under the jurisdiction of YAO. YAO collects data from Mexico, the All-American Canal users, the Gila Gravity Main Canal users, North Gila Canal, various Indian Tribes, PVID reservoirs, etc. These data are combined and sent to the water scheduling office located at the Hoover Dam facility. The lower Colorado River dam’s schedulers profile hourly releases using the electric service customer's energy load profiles. Water from Parker Dam has a 3-day travel time to Imperial Dam, a major diversion point for irrigation. Elevated water releases on Saturday and Sunday, when power is in less demand and revenue is less, will arrive at Imperial Dam on Tuesday and Wednesday, workdays for the growers. Conversely, low releases on Wednesday and Thursday (when power has a higher "weekday" value) will arrive at Imperial Dam on Saturday and Sunday, not typically workdays for the growers. These profiles are coordinated with WAPA’s power schedulers in Phoenix, Arizona, and the control room operators located at Hoover Dam. The "Parker Schedule Today," Figure 14a, is an example of the hourly projected release schedule. Between 2 p.m. and 3 p.m. the current day's schedule is revised and the next day's schedule is set by Hoover water operations schedulers to meet the daily required downstream water release and to incorporate any changes. The control room operator normally fine tunes the hourly release flows (see hand-marked changes) between the hours of 8 p.m. and 12 midnight daily to stay within plus or minus 40 cfs of the total scheduled downstream requirement. The "Parker Actual Release," Figure 14b, shows actual historical hourly release data for the Parker Dam facility. The Parker generating units are not normally placed on dynamic control (dynamic control causes the units to fluctuate on a 4-second interval), which would subject them to unscheduled river flow changes, which minimizes hourly downstream fluctuations. The hourly flow changes begin at 10 minutes to the hour and are fully implemented 10 minutes after the hour. These flow changes are computer controlled, and varying rates of unit releases over time can be changed.

The second reach starts at the Parker Dam facility and goes upstream to the Davis Dam facility. Water schedulers collect data from CAP, MWD, and others who divert from this reach of the river. These data are added to the Parker Dam facility's total scheduled plant water releases, and while considering flood control reservoir elevation on Lake Havasu, the total daily water releases are calculated for Davis Dam. The flood control reservoir elevation requirements for Lake Havasu are shown in Figure 15. The hourly release profile is determined by electric service customer requirements, the current downstream river needs, and upstream Lake Mohave requirements. Between 2 p.m. and 3 p.m. the current day's schedule is revised and the next day's schedule is set by schedulers to meet the daily required downstream water releases and incorporate any daily changes. The control room operator, located at Hoover Dam, normally fine tunes the hourly release flows between the hours of 8 p.m. and 12 midnight daily to stay within plus or minus 300 cfs of the total scheduled downstream requirement.

The third reach starts at Davis Dam and goes upstream to Hoover Dam. Reclamation combines the total estimated daily water release requirement of Davis Dam and the target Lake Mohave elevation to determine monthly the amount of water required downstream of Hoover Dam. This monthly release is formulated into a monthly energy figure. The monthly energy figure is sent to WAPA and the estimated daily energy schedule is set by its power scheduling personnel. The Hoover Dam generators are set on Automatic Generation Control (AGC) which follows the power system’s actual dynamic demands (See Figure 16, Typical Dynamic Power Generation). This graph represents the dynamic energy changes for each hour. The actual downstream water flow releases follow these patterns exactly. These monthly water and power figures are monitored by the scheduler. If the Lake Mohave elevation approaches the set high/low constraints, the scheduler coordinates with WAPA’s power scheduler in setting a new energy target if necessary (See Figure 17, Lake Mohave Operational Constraints graph).

The Lake Mohave operational constraints are not to drop the lake’s elevation more than 2 feet in any 10-day period between February and April. During this time period, energy is targeted for a 10-day period. The lake's elevation is not allowed to drop below 640 feet msl between April and the end of July and remains above elevation 637 feet msl until after September 16th. These voluntary constraints (represented by curve A in Figure 17) are for a 5-year period ending in 1998 and are to accommodate the Razorback Sucker Program. After this 5-year period, the future operations of Lake Mohave will revert to the pattern shown on curve B in Figure 17.

There are four seasonal release patterns for the three facilities - Hoover Dam, Davis Dam, and Parker Dam. Figures 18, 19, and 20, respectively, show the Hoover, Davis and Parker Dams’ normal hourly release pattern for a representative day in each of the four seasons. The curves show a flatter water release for Parker Dam than for Davis Dam; with Hoover Dam releases taking most of the fluctuations. This is due to the fact that Hoover Dam normally releases water directly into Lake Mohave, which serves to stabilize river fluctuations. Hoover Dam is used to respond to power system fluctuations because it responds quicker, more efficiently, and with the least disturbance to the river system.

Under the authority of the CRFWLS Act of March 3, 1925, as amended, Reclamation maintains the channel, banklines, levee systems, and control structures along the lower Colorado River. This includes 168 miles of stabilized banklines, 114 miles of levees and 75 associated river structures including jetties and training structures. For administrative purposes the reaches of the river from Davis Dam to the SIB are divided into maintenance divisions, which are roughly determined by different physical characteristics as identified in Figure 2. A description of each division is presented in Appendix C.

The routine maintenance on existing stabilized banklines consists of placing riprap on bankline areas where the existing riprap has eroded or otherwise needs repair. Other routine maintenance involving riprap includes repair of jetties and training structures. Again, this repair consists of replacing riprap where it has eroded or otherwise needs replacing. Some riprap is needed occasionally for repair of levee armoring.

Associated with the maintenance of the banklines, levees, and river control structures is maintenance of access and bankline roads. Roads are maintained on the levees and adjacent areas to stabilize banklines. The maintenance is routine road repair required for gravel roads. While these roads are also used by the public for various reasons, the roads are maintained for operation and maintenance of Reclamation project facilities and are not maintained up to public road standards.

Riprap and gravel for the above maintenance activities are obtained from various stockpile sites located along the river if the work is conducted by Reclamation personnel. As a rule, quarrying activities are conducted to produce and maintain stockpiles of rock and gravel along the river for emergency flood control purposes and routine maintenance described above. In general, quarrying and hauling activities are contracted when it is determined the stockpiles need to be replenished. This replenishment could be necessary after a long period of time if the stockpiles are used only for routine maintenance, or after a short period of time if a high-flow emergency occurs. In some cases, if extensive repairs are required to stabilize banklines, levees, and river control structures, the work is contracted to private enterprise. In many of those cases, quarrying activities occur and the riprap and gravel are hauled directly from the quarry.

Reclamation routinely dredges two types of areas: sedimentation basins and backwaters. Reclamation maintains two dredging basins -the Topock Dredge Basin located near Needles, California, and the Laguna Dredge Basin, located between Imperial and Laguna Dams. In addition, Reclamation routinely dredges material from the headworks of the All-American Canal and the Gila Gravity Main Canal at Imperial Reservoir. These dredging operations are confined to the areas mentioned above. The dredging uses a hydraulic dredge, and the material is deposited on spoil areas proximate to the dredging basins. In the case of the headworks of the All-American Canal and the Gila Gravity Main Canal, the dredged material is deposited into the California Sluiceway below Imperial Dam and sluiced to the Laguna Dredge Basin for removal.

Reclamation also conducts dredging operations for mitigation maintenance on backwaters which have been identified for maintenance to restore their fish and wildlife functions. In addition, Reclamation will cost share enhancement dredging for other backwater wetlands along the lower Colorado River. Reclamation conducts separate ESA consultations for those mitigation and enhancement projects. While those projects could be a routine part of Reclamation activities, the scope of the projects generally warrants separate ESA and National Environmental Policy Act (NEPA) compliance.

The YDP, completed in 1992 and located about 6 miles west of Yuma, Arizona, was constructed to enable the United States to comply with its water quality obligations under Minute No. 242, an extension of the 1944 Treaty with Mexico. The YDP is currently maintained in ready-reserve to enable future activation if required.

The 5-mile zone is a 36,000-acre area 10 miles south of Yuma, Arizona, containing Reclamation-acquired and other lands needed to construct, operate, and maintain a well field to provide water to Mexico in partial fulfillment of the 1944 Treaty and as required by Title I of the Salinity Control Act. Reclamation maintains the 21 wells in the well field, the associated delivery canal, and the YDP sludge disposal site. A description of the operation and maintenance of the YDP and 5-mile zone is provided in Appendix F.

In addition to the previously described Colorado River operation and maintenance activities, Reclamation also has an ongoing program of endangered species conservation. These activities are authorized and executed pursuant to section 7(a)(1) of the ESA. The activities range from being very specific in nature to the broad multi-species conservation program (Appendix A). Reclamation’s endangered species conservation activities, that are currently underway or that are anticipated to occur within the next 5 years, are described below.

Reclamation has an active program for the conservation and recovery of endangered razorback suckers and bonytail. These activities are being done under section 7(a)(1) of the ESA and are part of our current routine operation of the lower Colorado River. As part of the lower Colorado River MSCP interim conservation effort, Federal and State biologists met in July of 1995 to prioritize and quantify recovery and conservation program needs for endangered fish and other species during the 1995-2005 period (Appendix G). The specific immediate needs for razorback sucker and bonytail are summarized as follows:

These needs encompass and include the goals of the Native Fish Work Group (NFWG) and Lake Havasu Fishery Improvement Project (HAVFISH) described below.

Reclamation is committed to providing the resources necessary to achieve at least half, if not more, of the quantified goals for the two species. The programs described below represent some of the ways this is currently being or will be achieved.

The NFWG on Lake Mohave was formed in 1989 as an initiative of Reclamation biologists Gordon Mueller and Tom Burke. In addition to Reclamation, the original member agencies were Nevada Division of Wildlife (NDOW), Arizona Game and Fish Department (AGFD), FWS, NPS [Lake Mead National Recreation Area (LMNRA)], and Arizona State University (ASU). The primary purpose of the NFWG was to replace the aging population of adult razorback suckers resident to Lake Mohave. Replacing the sunset population of razorback suckers with immature fish spawned by Lake Mohave’s wild population will maintain the population’s genetic diversity and viability.

For many years, biologists observed adult razorback suckers coming into shoreline areas on Lake Mohave to spawn. While larvae were produced from these efforts, recruitment into the adult life stage was not occurring. Minckley (1983) documented a pattern of disappearance of razorback sucker from Colorado River basin reservoirs 40-50 years after initial impoundment. Studies conducted on adult razorback suckers from Lake Mohave during the mid-1980s showed the fish to be 24-44 years old and predicted the collapse of the Lake Mohave population by the turn of the century (McCarthy and Minckley 1987).

Experiments were conducted at Yuma Cove on Lake Mohave in 1985-87, wherein adult razorback suckers were removed from spawning grounds and placed into a predator-free lakeside pond, Yuma Cove, which produced young suckers of a size larger than found in the lake proper (Marsh and Langhorst, 1988). At that time, Yuma Cove was separated from the main lake by a low, natural berm comprised of wave-washed sand and gravel. This berm was breached by wave action in 1985, and predatory fishes from the lake accessed the backwater pond. When the berm again breached in 1987, the project was terminated.

The first action taken by the NFWG was to rebuild the sand and gravel berm at Yuma Cove to a more secure level. The group then removed all fishes from the pond with an ichthyocide and then stocked it with ripe adult razorback suckers. The first success was in 1992 when 150 young fish were reared to over 10 inches in length and released to the lake. In 1993 the NFWG expanded its activities to other lakeside ponds and reared some 500 fish for release into Lake Mohave. In 1994 NFWG started focusing on using younger life stages by collecting 10,000 wild larvae from spawning areas around the lake and placing them into the lakeside ponds. This resulted in over 2,200 young fish being reared and released to Lake Mohave. The effort increased in 1995 with almost 20,000 larvae being captured. Of these, half were stocked in lakeside ponds for rearing to release-size during that year and half went to Willow Beach National Fish Hatchery (WBNFH) for rearing to juvenile stages to then be stocked into lakeside rearing ponds in January 1996. The 1995 results were similar to 1994 (except that the fish were larger at time of release), with some 2,000 fish being reared and released to the reservoir. Over 100 of these fish have been recaptured at spawning grounds during spring surveys, completing the cycle of recruitment to adulthood.

As a charter member and lead agency in the NFWG, Reclamation is committed to spending at least $250,000 per year on capturing "wild" razorback sucker larvae from Lake Mohave and providing for their rearing in predator-free environments on or near the lake.

The program was aided in 1996 by increased funding from Reclamation as part of its commitment to the MSCP (described earlier in this report). NFWG was able to capture over 60,000 wild razorback sucker larvae. These fish are presently rearing in either lakeside backwater ponds or in modified raceways at WBNFH. The NFWG has included rearing of bonytail in its program and has successfully reared and stocked almost 500 fish since 1994. Reclamation is committed to this program and its goal to replace the Lake Mohave population of adult razorback suckers.

Since 1994, Reclamation has been working with FWS at WBNFH to retrofit portions of this cold water facility in order to rear native warm-water fishes. In 1994, Reclamation engineers designed and installed heating systems for the hatch house for initial rearing of eggs and larvae. Approximately 8,000 young razorback suckers were produced and reared for stocking into rearing ponds at Lake Havasu. In 1995, the first of six paired outside raceways received solar-heated water in a closed circuit loop, providing a warm water rearing area for razorback suckers and bonytail. In 1996 and 1997, five more raceway units will be developed. Reclamation is also providing funds and staff for feeding and maintaining the fishes in these modified facilities. Reclamation is committed to this cooperative program with FWS to develop warm water rearing capabilities at Willow Beach. As part of the MSCP (also described below), Reclamation is providing staff support to Willow Beach through 1998 to accelerate the native fish rearing program.

Reclamation is an active partner of the multi-agency, Lake Havasu Fishery Improvement Project, HAVFISH. One of the objectives of this multi-agency program is to release 25,000 razorback suckers and 25,000 bonytail into Lake Havasu over the next 10 years. Reclamation has provided technical and monetary support for this program since its beginning. As a full and active partner, Reclamation is committed to the goals of the program regarding native fish recovery and is working with FWS in the development of a native fish rearing facility on the CRIT reservation near Parker, Arizona.

Reclamation and NDOW signed an interagency agreement with the City of Boulder City to use the ponds at Boulder City Golf Course for rearing of native fishes. During 1994 the first lake on the course was drained and a new liner and aeration system were installed. In October 1994 approximately 1,400 juvenile razorback suckers (3-4 inches total length) were stocked into the pond. During 1995, over 400 of these suckers reached the target length of 10 inches and were stocked into Lake Havasu. During the 1996 spring spawning period, at least five of these fish were captured in Lake Mohave. This program is expanding with the development of three more ponds on the golf course, one each in 1996, 1997, and 1998.

Reclamation is providing technical and financial support to the Hualapai Tribe in northern Arizona for the development of a prototype native fish rearing facility. This facility may raise razorback suckers, bonytail, humpback chubs and other native fishes for reintroduction into the Colorado River and its tributaries within Grand Canyon and on tribal lands. The assessment of this potential project began in 1992 and is expected to continue.

Reclamation is committed to maintaining and expanding the cooperative native riparian plant restoration programs initiated along the lower Colorado River. These partnership activities include the establishment of native plant nurseries, demonstration plantings, enhancement projects, and research. Reclamation will commit at least $100,000 per year for the 5-year period covered by this document for native riparian plant restoration.

Reclamation, in cooperation with FWS, has established three native riparian plant nurseries along the lower Colorado River. These nurseries have been established on Imperial National Wildlife Refuge, Cibola National Wildlife Refuge, and Havasu National Wildlife Refuge. In addition, Reclamation has established a fourth nursery in conjunction with the NPS at Lake Mead. Plant material from these nurseries can be utilized for restoration or enhancement projects by any of the cooperating agencies. Reclamation is committed to expanding these nurseries when desirable.

Reclamation, also in cooperation with FWS, has established a series of demonstration areas along the lower Colorado River. As of 1996, 20 acres have been planted in 5 different plots. The main objective of this project is to study the biotic and abiotic factors influencing the survival and growth of native riparian species along the lower Colorado River. Reclamation is committed to the continuous monitoring of these sites and the establishment of future sites, contingent upon future funding levels and the signing of cooperative agreements with other agencies or groups.

Reclamation and FWS have been involved in cooperative efforts to enhance native riparian habitat along the lower Colorado River. Approximately 200 acres will be revegetated between 1993 and 1998. Reclamation is committed to providing staff, materials, and/or funding to continue this effort, especially with wildlife refuges.

Reclamation has entered into a cooperative agreement with the United States Department of Agriculture’s (USDA) Agricultural Research Service to screen and select genotypes of four native riparian plant species for salinity tolerance. Clonal material from any genotypes exhibiting a higher degree of salinity tolerance will be stocked in nurseries along the lower Colorado River for use in future revegetation efforts. Reclamation has committed $100,000 annually for 2 years to conduct this project. Results are due in the fall of 1996.

In 1993, Reclamation and FWS began a cooperative project to restore Three-Finger Lake (Figure 21). Approximately 120 acres of channels and shallow backwater areas, plus one 20-acre native fish rearing pond, were dredged in 1995. The final phases of this project, including construction of the water intake system, the construction of protective levees and bankline structures, and the planting of native riparian vegetation will be completed by spring of 1997. The total of this cost-share project will be approximately $4 million. Reclamation has spent $2.5 million from 1995-96 on the Three-Finger Lake restoration project. The project will provide habitat for native fish and native (e.g., Yuma clapper rail) and migratory fauna such as the willow flycatcher.

The primary objective of the Boulder City Wetland Project is to demonstrate using reclaimed municipal wastewater to restore habitat for threatened and endangered species and species of concern. Secondary objectives include public education and research on improving water quality and restoring habitat for sensitive species. Reclamation’s authority for the project piggybacks section 7(a)(1) of the ESA onto section 1605, Title 16 of the Reclamation Wastewater and Groundwater Study and Facilities Act (P.L. 102-575). The latter section provides Reclamation with the authority to construct and operate cooperative, cost-shared research and demonstration projects for reclaiming wastewater. The project is being cooperatively developed and funded by the City of Boulder City, Reclamation, NDOW, Clark County Conservation District, USDA Natural Resource Conservation Service, and National Biological Service. Reclamation’s contribution towards the project will total $400,000 and will consist of in-house biological, geological, and engineering expertise and funding required for project construction.

The Boulder City Wetland will receive Colorado River water blended with treated wastewater from Boulder City's wastewater treatment plant. The blended wastewater will flow through a wetland system consisting of a ½-mile-long stream containing shallow marshes and pools, then through four 1-acre deep-water ponds (Figure 22). The stream and ponds will contain a variety of native wetland plants and be bordered by native riparian plantings. Water from the wetland will be used to irrigate turf at an adjacent Veterans Cemetery. In this manner, maximum benefit will be obtained from Boulder City's wastewater.

The variety of wetland and riparian habitats restored are being designed to maximize the number of species benefitting rather than focus on only a few species. Targeted species will include the southwestern willow flycatcher and several fishes such as razorback sucker and Moapa, Oasis Valley, and Pahranagat speckled dace. Habitat will also be restored for an insect species of concern: MacNeill’s sootywing skipper.

Project planning was initiated in March 1995, and final designs for the project were completed in September 1995. Construction began in November 1995 and will be completed by November 1996. Following completion, a monitoring program will be initiated to evaluate the quality of the habitat restored and the success of establishing populations of sensitive species.

This proposed cost-share project will restore and maintain streamflow of sufficient quality and quantity to enhance and assist in recovering and protecting riparian/wetland and aquatic fish and wildlife habitat. The proposed project extends from Imperial Dam upstream to Martinez Lake and encompasses a 9.5-mile reach of the lower Colorado River including about 3,000 acres of riparian habitat and wetlands and 22 backwater lakes (Figure 23).

The area is extensively used by waterfowl, neotropical birds, sport fish, amphibians, mammals, song birds, and other wildlife. This reach of the river is also heavily used by hunters, fishermen, campers, skiers, boaters, and jet skies. The life of the project is estimated to be 30 years.

The Interagency Backwater Subcommittee of the Lower Colorado River Work Group has identified and recommended this reach of river as a priority for restoration and enhancement. The subcommittee also recommended the formation of an ad hoc committee, consisting of representatives from the BLM, FWS, AGFD, California Department of Fish and Game (CFG), and Reclamation to organize and plan the restoration and enhancement project. The final plan should be completed by August 1996, and will include additional restoration and enhancement on the Imperial National Wildlife Refuge. Separate section 7 compliance has been completed for the Yuma clapper rail and razorback sucker but is needed for the southwestern willow flycatcher.

Project objectives for the California and Arizona sides of the river are as follows:

Reclamation and NPS have entered into an agreement to construct two new wetlands totaling approximately 20 acres on the lower end of Las Vegas Wash near its discharge to Lake Mead. These two multi-purpose wetlands are designed to enhance marsh and riparian habitat within the eroded channel of the wash and also to provide for the polishing of perennial effluent flows. NPS has the compliance lead for this effort to enhance the habitat for the benefit of aquatic and riparian-dependent species.

The lower Colorado River MSCP is a cooperative Federal-Lower basin States-Tribal-Private effort to conserve ESA-listed and sensitive species dependent on the river. DOI and the lower Division States have committed to cooperate and cost share (1:1 ratio) in the development of the MSCP, and the active participation of Native Americans, environmental and other interests are being encouraged. This program has the goal of benefitting more than 100 Federal- or State-listed, candidate and sensitive species and their habitats, ranging from aquatic, wetland and riparian, to upland. Additional information on this proposal is provided in Appendix A.

As part of the MSCP development process, Reclamation has dedicated resources to initiate the process and has agreed, along with other DOI agencies, to pursue additional resources, subject to Congressional authorization and allocations, to complete the cooperative development of the MSCP over the next 3 years. In this regard, Reclamation has provided funding for program development and interim conservation measures (see previous conservation discussion), as specified in the June 26, 1996, cooperative funding agreement(Appendix A). Reclamation’s funding commitment for fiscal year 1996 is $300,000.

As proposed the MSCP will address Federal and non-Federal activities on the lower Colorado River for a 50-year period. Although the MSCP is envisioned as a single multi-party-sponsored program, ESA compliance for Federal and non-Federal actions will be conducted separately under the provisions of sections 7 and 10, respectively. Specific future Federal and non-Federal actions have not been quantified at this point, but will be since the final MSCP will require its own NEPA and ESA compliances. During the development of the MSCP and to meet its section 7 consultation obligations, Reclamation has provided this BA and requested formal section 7 consultation on its present discretionary routine operations and maintenance.

The preceding sections presented an overview of the complexity of the Secretary’s management of the lower Colorado River. His discretion and lack of discretion in managing the lower Colorado River are defined, as referenced several times, by the "Law of the River." As such, the Secretary, acting either directly or through Reclamation, is the Watermaster of the lower Colorado River basin. The following is a summary of the Secretary’s discretionary and non-discretionary management activities on the lower Colorado River. The discretionary activities are those that are subject to the formal section 7 consultation initiated by this BA.

The Secretary has no meaningful discretion in the following activities:

The Secretary has varying degrees of discretion, in some instances contractually burdened, on several operation and maintenance functions. Due to the complexity of the "Law of the River" regarding many of the following aspects, Reclamation has not gone to extraordinary detail to quantify which of a myriad of possible scenarios is discretionary or non-discretionary. Instead, the biological analysis contained in this BA assumes that the Secretary will abide by all existing contractual obligations and will not act unilaterally to void such arrangements. Additionally, the Secretary is obligated to fulfill the provisions of applicable Code of Federal Regulations (CFRs), several of which have been cited in this document. Without such presumptions, this document would lack an analytical framework from which to analyze either the Secretary's projected management actions on the lower Colorado River, or the biological effects of such actions.

However, in the event that the FWS determines that Reclamation's actions may cause jeopardy to a species and/or the adverse modification of critical habitat, Reclamation will work with FWS to determine whether any potential RPAs can be implemented consistent with the scope of the Secretary's legal authority and jurisdiction, along with the additional considerations set forth in 50 CFR 402.02. Also, the Secretary has the discretion to renegotiate contracts or reach voluntary agreements with contractual partners; and the Secretary has the discretion to initiate the review and revision of applicable CFRs.



Chapter I TOC | Chapter II TOC | Chapter III TOC | Chapter IV TOC
Glossary of Terms and Acronyms | Appendices | Tables | Figures
Assessment TOC | COMMENTS