|
| |
Snake River Watershed Project
The city of Warren has endured numerous floods throughout its history. In
1996 and 1997 alone the city suffered three major floods that caused 12.7
million dollars in damage. In 1997 the USDA Natural Resources Conservation
Service (NRCS) was asked by the local sponsors, the city of Warren and Middle
River-Snake River Watershed District, to resume planning on the Snake River
Watershed Project. Planning on this project was started in the 1980’s but had
been terminated at the sponsor’s request. In November 1999, the planning for
this project was completed.
Main Street of Warren, Spring 1996
When complete, the Snake River Watershed Project will provide 100-year frequency
flood protection for the city of Warren. The project consists of two main
components, an excavated floodway around the city of Warren, and floodwater
storage impoundment located upstream of the city. The floodwater storage
impoundment was needed to ensure that flood levels would not be increased
downstream of Warren or upstream of the floodway diversion structure.
The floodway safely carries flood flows around Warren
The floodway Storage Reservoir in
Comstock Township will reduce peak flows downstream
Engineering and funding for the flood
control components are being provided by the USDA-NRCS under the Public Law 566
Watershed Protection and Flood Prevention Program. The local sponsors are
responsible for purchasing right-of-way, installing road crossings, and
contracting for construction. The Middle River-Snake River Watershed District is
also responsible for future operation and maintenance of the project.
The Snake River groundbreaking ceremony for the watershed project was held on
October 26, 2001.
Phase I of the project consisted of
the lower mile of the floodway and outlet chute was awarded to KGM Contracting
of Angora, Minnesota for the price of $562,000. This phase of the project was
completed in August 2002.
The Phase I Floodway is seeded and mulched
Rock is placed for the floodway outlet chute
Phase II of the project is the Off
Channel Floodwater Storage Reservoir. In May 2002, the construction contract for
this phase was awarded to Riley Brothers Construction of Morris, MN for a price
of $4,362,000.
Out on the Phase II site are Bruce
Julan, NRCS, Washington D.C.,
Ron Adrian, Middle River-Snake River Watershed District, and
Richard Nelson, Mayor, city of Warren
The off-channel storage structure portion of the project has been completed and was in operation in
time for the spring thaw in 2005. The majority of the work was completed in
the fall of 2004. The off channel storage area has a foot print of about 550
acres with a flood pool storage capability of about 6800 acre-feet. The
earth embankment is close to 4.5 miles long with the highest fill section
being approximately 22.5 feet high. More than 1.3 million cubic yards of
earth fill was required to construct the embankment. Spring 2005 saw about
1400 ac-ft of water stored in the OCS. During the month of June the area saw
heavy rains which brought the pool area back up around 1400 ac-ft.
Outlet Structure – Off Channel Storage
Inlet Structure to Off Channel Storage Area
Phase III of the Project
includes the Snake River Diversion Structure and
upper 3 miles of floodway. The diversion structure will allow low flows to
continue through the city of Warren, but will divert high flows into the
floodway. The diversion structure includes a fish passage structure to allow
fish passage for a wide range of flow conditions. Phase III has been closely
coordinated with the construction of three highway and two railroad crossings
which has been constructed concurrently.
The diversion and
floodway portion of the project is currently under construction.
One mile of floodway was constructed in 2001 and 2002 and another
mile was constructed in 2003. The final 2.2 miles was finished
the summer of 2005. The total floodway length was about 4.2 miles and
the total excavated quantity was over 900,000 cubic yards.
 Floodway excavation using the GPS equipped dozer
 Floodway seedbed preparation after excavation
 Installation of permanent turf reinforcement mat
 Floodway after seeding and mulching
The last placement of
concrete for the diversion structure was on November 30th 2005.
The diversion structure is 182 feet long, 26 feet high, and has a 10
foot deep cutoff wall. It is also constructed to allow fish
passage through the structure. A total of 1,236 cubic yards of
concrete was placed and over 400,000 pounds of steel reinforcement
was used to construct the diversion.
The remaining work
consists of backfill for the concrete structure as well as placing
some riprap for protection upstream and downstream of the structure.
There is also some earthwork to be finished along with the final
seeding and mulching. It is expected that all work on the
floodway and diversion portion of the project will be completed the
summer of 2006.
 Installation of reinforcing steel in cutoff trench
 Preparation for placement of the main slab
 The first 15 feet of the wall is in place
 Forming the final wall placement.
Phase IV of the project will
include the construction of wetlands and tree plantings required as mitigation
for those lost during the construction of the project.
Last Modified 12/21/2005
| |
|
About Us
Back to Top