Project Description & Samples

This page provides information for preparing project descriptions for environmental reviews.

Project Description

• For the purpose of environmental review, a good project description should contain the following:
  1. A clear and detailed written description (including all components) of the entire scope of work. This should also include:
     1. All other alternatives (projects) that have been considered as solutions to the situation.
         
     2. Any additional work-funded by other sources-to be performed substantially the same time.
         
  2. Studies, plans drawings, sketches and schematics that can be used to understand the entire project.
      
  3. Photos, drawings and maps showing the proposed area and site in the context of its surroundings.
      
  4. If the project is a building(s) acquisition, date of construction.
      
  5. If the project is in a rural setting (such as bridges, culverts, drainage reworks/diversions, sewage lagoons, etc.), drawings, diagrams or maps showing the general land, unique features and water features at or near the project site.
      
  6. Location maps such as city maps or USGS 7 1/2 quad maps if appropriate along with any photographs that may be appropriate.
      
• If more detailed information is needed, please contact the Regional Environmental Officer or Program Environmental Coordinator.
   
• See sample project descriptions below.

Sample Project Descriptions

1. Flood Prevention for County Courthouse

The county courthouse is a historic building that is located in the oldest town in the state. Over the past few years several "localized" floods have occurred in the two-block region surrounding the courthouse. These floods develop as a result of rainfall events that are at or near the yearly maximum. The floodwaters have flowed both into the historic courthouse (photos were provided) and the adjoining annex, bordering the parking lot to the east of the courthouse. The floods originate in the vicinity of the parking lot and flow south and west into the courthouse complex, exiting onto the downhill streets adjacent to the courthouse (photos were provided).

The repeated flooding events are partially caused by an unusually high water table in this small area. The water table has hit the ground surface in some locations to produce artificial springs. When rain occurs there is little or no infiltration and virtually all of the water flows downhill on the surface as overland flow. Thus a normal rainfall event can lead to water depths on the ground that would be greater than those associated with a twenty-year flood.

The water table is sufficiently high that the foundation of the courthouse is continually wet and the crawl space below the building has standing water in it. The courthouse is made of adobe and the walls have "wicked" the groundwater upwards into the building. The moisture is evident in the walls of the building (photos were provided). The moisture invaded the drywall and when the interior walls were removed to examine the adobe core, plants were found growing in the adobe. Some of the walls are beginning to collapse, and the courthouse has been vacated. In mid-August the (state) Historical Society would like to begin the process of designing and restoring the historic building. In talking with representatives of the Historical Society, they believe that the flooding problem needs to be solved prior to restoration. They said, "The flooding is the horse, the restoration is the cart, and we must not put the cart before the horse."

During the previous year the town constructed a storm drainage system. The project did not include the two-blocks of the courthouse complex because the county owned it. Reports associated with this project indicate that the groundwater table is normally about seven feet below surface level in monitoring wells located about fifty feet west of the courthouse. The unusually high water table in the courthouse block appears to be the result of leaking artesian wells. One leaking artesian well was found in the parking lot of the courthouse complex (photos were provided). The water from this leaking well runs across the parking lot in an open, unlined ditch.

The final design of the flood prevention grant will be coordinated by the community Project Impact team but jointly designed by the United States Geological Survey (USGS, Hydrology Division - city office) and an engineering service located in the county. The location of the artesian wells in the courthouse complex will be determined using metal detectors and laborers supplied by the county. Measurements on water flow in these wells will be conducted by the USGS. The firings of new caps will be overseen by the engineering service, liking via subcontracting to a local drilling company.

Historically artesian wells have supplied much of the water to the residents of the town. A walking tour of the city surrounding the county courthouse indicated one or two artesian wells per block. It seems reasonable to expect that fixing the town known artesian wells in the courthouse region (plus perhaps one or two additional unknown wells) will stop the artificial discharge of artesian water into the zone and allow the water table to drop back down to its natural level. The work will be conducted in July and August and the groundwater should return the normal levels in time for a successful restoration of the courthouse.     

2. Storm Sewer Project

There is currently a 48" storm sewer located on South Federal Boulevard. This storm sewer collects and transmits runoff from over 250 acres of urban developed land within the city. Currently the lower end of this 48" storm sewer is over capacity during large rainfall events. The result is that manhole lids for this storm sewer are "blown off" at the lower end of this system during large rainfall events due to the quantity of water building pressure within the line. Note that this storm sewer transitions from a rather steep grade downstream to a rather flat grade. The net result is flooding of the lower portion of the city (Fairgrounds area) during large rainfall events.

In 1981 the city commissioned and received a Storm Drainage Master Plan. An engineering corporation located in the city prepared this plan. This corporation is no longer in existence. This plan utilized the U.S. Soil Conservation Service computer model entitled "Technical Release 20 Computer Program for Project Formulation" using the 100-year recurrence interval for this analysis.

This project has been in the planning stage since at least 1981. This project is the first step (phase I) in a two-step process to reduce the storm drainage flow down the existing 48" storm sewer on South Federal Boulevard. The second step (next project, phase II) consists of constructing a diversion dam and detention basin just south of, and adjacent to the open drainage ditch (Big Bend Ditch). Once both phases are completed, flow will be diverted from the 48" existing storm sewer to the Big Bend Ditch and detention pond.

This report states that along South Federal Blvd. (a planning sheet was provided) there will be an estimated 55 CFS flowing through the existing 48" storm sewer for a 100-year event. The 55 cfs that currently flows to the south in the existing storm sewer will be diverted to an existing open drainage ditch (Big Bend drainage ditch) that flows east and will flow into a detention basin to be constructed during phase II of this project. This will then leave the full capacity of the existing 48" storm drain, which is estimated at 55 cfs, available to transmit the storm water from that point south.

This project will consist of the following:

1. Construction of a diversion box on the existing 48" storm sewer on South Federal Blvd. This concrete box will contain a concrete wall running east to west, 27 inches in height. This wall will be located just downstream of the proposed 27" storm sewer exiting the box to the east. During a large rainfall event, the new 27" storm sewer line will fill first (due to the 27" concrete wall). The excess runoff will flow over the wall (yet still be within the diversion box structure) and flow down the existing 48" line to the south.
    
2. A 36" diameter steel casing pipe will be bored and jacked under the highway (South Federal Blvd.) from the east right-of-way line to the west right-of-way line. Note that no "open cutting" of the highway is planned at this time.
    
3. A 27" PVC storm sewer will be installed and centered within the casing pipe under the highway.
    
4. The 27" PVC storm sewer will continue (photos were provided) to outfall into the open ditch.
    
5. Three manholes will be installed on this new storm sewer at changes in alignment. Note that a manhole has been added east of and adjacent to the highway right-of-way.
    
6. An existing steel culvert that is currently half silted in will be replaced with two new 36" culverts. These culverts are located within the Big Bend Ditch (open drainage) (photos were provided).
    
7. A second existing steel culvert that is also half silted in will be replaced with two new 36" culverts. These culverts are located within Big Bend Ditch (open drainage) (photos were provided).

This project (phase I) will be constructed on previously disturbed grounds. Note also that the highway right-of-way limits and their relation to this project were shown in an attached planning sheet.

3. Acquisition/Relocation/Demolition

This project consists of the acquisition of flood damaged properties located adjacent to the Park River (in the floodway) (photos were provided). Nineteen (19) properties have been identified as having substantial damages and are at high risk for future flood damages. Once acquired, these structures will be put up for bid for relocation outside the 100-year floodplain. Any unsold homes will be demolished and removed. The sites will then be deed restricted and become green space.

Nine (9) of these homes have historical significance. Photos of the homes have already been taken and preliminary discussions with the SHPO have begun. The SHPO has requested a CRI III which will be completed after project approval and before the project begins.

4. A Set of Detention Ponds

(A project vicinity map was provided). Construction of the ponds is intended to detain stormwater flows generated by 134.4 acres of undeveloped land between two hogbacks on the west side of town. Currently, stormwater flows exit though openings in the eastern-most hogback and regularly overwhelm collection facilities in the historic downtown and adjacent residential areas. Further, because of the steep, undeveloped nature of the tributary drainage basins, stormwater flows carry substantial amounts of sediment. This material ultimately deposits on City streets and in stormwater collection facilities exacerbating flooding and necessitating regular cleanup and repairs.

In addition to a No Action alternative, detention ponds providing two levels of protection have been evaluated for mitigation of flood and sediment deposition problems. The two detention pond alternatives are referred to as the Partial Detention Alternative and the Full Detention Alternative.

Partial Detention Alternative

The Partial Detention Alternative is the flood mitigation scheme as proposed in the Hogback Detention Master Plan by Graef, Anhalt, Schloemer & Associates, Inc. (February, 1995), commissioned by the city. The plan calls for seven (7) small detention ponds to be formed by constructing low height dams across openings in the lower, eastern hogback. During storm events, ponding behind the dams would remove sediment and reduce peak flows by approximately 50 percent. Volumes of water stored during the 100-year storm would range from 0.4 to 2.0 acre-feet, maximum ponding depths would range from 3.3 to 5.2 feet, and the inundated area would range from 0.15 to 0.35 acres. Outlet works for each of the basins would consist of an 18- or 24-inch diameter corrugated metal pipe (CMP) through the dam discharging to an improved ditch. The ditches would convey reduced stormwater flows from the base of the east hogback to City collection facilities, a distance ranging from 250 to 1,100 feet. Ditches would be trapezoidal in shape, 2 feet wide at the bottom and 3 feet deep with 2:1 (horizontal:vertical) side slopes. At the pond outlet and along steeper reached of each ditch, rip rap lining will be required.

Full Detention Alternative

This alternative utilizes the same seven detention ponds as the partial Detention Alternative, but the ponds would be enlarged approximately 300 percent to provide storage for the full volume of the 24-hour, 100-year storm hydrograph. Under this alternative the volume of proposed ponds would range from 1.2 to 5.3 acre-feet. The additional volume would be provided through a combination of excavation and increased dam height. The proposed height of dam structures (and 100-year ponding depths) would be increased to 10 feet at the weir crest. At this height, all of the dams would be non-jurisdictional structures and therefore not subject to state review or inspections. Inundated are for the ponds would range from 0.25 to 0.65 acres. Small diameter outlets would reduce peak flows from the hogback drainage basins to a maximum of 3 cfs. Outlet works would consist of 12-inch diameter CMP's with 6-inch diameter orifice plates restricting the entrances. The lower peak discharge rates associated with the larger ponds would substantially reduce the required dimensions for outlet channels. Small trapezoidal ditches, 1 foot wide at the bottom, 1 foot deep and having 2:1 (horizontal:vertical) side slopes would generally be adequate.

Selected Alternative

Based on a benefit/cost analysis of "No Action" and the two alternatives describes above, the Partial Detention Alternative was selected as the Proposed Project. The largest of the seven proposed detention ponds under this alternative was constructed during the summer of 1995. The city's HMGP application will request funds for final design and construction of the remaining six (6) ponds. A vicinity map and locations for each of the seven detention ponds was provided.