Specifications

Section 6 The Selected Alternative Plan
EAA Storage Reservoirs Revised Draft PIR and EIS February 2006
6-13
TABLE 6-4: WETLANDS BUFFER AND LITTORAL ZONE
Feature Wetland Upland Littoral Shelf
50' Corridor to
Eventually
Return to Wetland
Ave. Width (ft) 60 50 30 50
Length (lf) 110,000 82,500 110,000 110,000
Area (Acres) 152 95 76 126
Totals 278 95 76
Notes:
1. Wetland and Upland average width is calculated by assuming an average depth of 1 foot.
Which results in an average Wetland strip width of 60 linear feet and 50 linear feet Upland.
2. It is assumed that the Seepage Buffer will occur all along the east, north, and west sides of the
project site for a total length of 110,000 linear feet.
3. It is assumed that the upland (tree islands) will occupy only 75% of the total length since it
takes 25% more material from the excavated wetland to built each linear foot of upland (i.e.
there will be only 75 linear feet of upland for each 100 of wetland.)
6.1.10.2 Deep-water Refugia and Littoral Zone
Deep water refugia are created by the existing agricultural ditches and
excavation borrow pits within the reservoir. The area of the borrow pits is
approximately 170 acres. The existing ditches and borrow pits provides fish
refuge during periods when the reservoir pool elevations approaches average
ground elevation. The littoral zone will be located along the length of the seepage
canal for approximately 110,000 feet. The shelf would be approximately 30 to
35-feet wide. The first 15-foot wide section would be contoured to a 1V:5H slope.
Where the caprock intersects the littoral shelf it will be sloped to the extent
practicable. The second 15-foot wide section would be contoured to a 1V:2H
slope. The littoral shelves would be constructed by scraping the peat layer
adjacent to the canals. The shelf should provide an estimated 76 acres of habitat
for fish and wildlife, especially wading birds.
6.1.10.3 Recreation
The justification of incurring additional costs for recreation features is derived
by utilizing a benefit to cost ratio. The detailed evaluation of these features is
presented in Appendix D. Because the total recreation features (Figure 6-5) was
the same for all action alternatives considered, only the selected alternative plan
was evaluated in Appendix D. These average annual recreation benefits and
costs are summarized in Table 6-5. The evaluation indicates there are 6.7 times
more benefits than costs. The benefit to cost ratio for the recreation features
equals 6.7 to 1, with net annual benefits equaling $185,700.