WSPC03939

• File Number: 8460.500
• Description: Platte River Basin - Endangered Species Issues - South Platte Recovery Program
• State: CO
• Basin: South Platte
• Water Division: 1
• Date: 12/5/1995
• Author: Matthew J Cook
• Title: South Platte Agreement - Groundwater Recharge as Augmentation for Restoring Wetlands Along the Central Platte River Nebraska - Final Report
• Water Supply Pro - Doc Type: Report/Study

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000675

K1

l'

r

K=

L
LI L2
-+-
KI K2

L

j I

Kz

Lz

'!

Where:

K=mean value, permeability in FtI Day
L= Thickness of Soil medium (ft)
L 1 = Thickness of Soil Layer 1 (ft)
L2= Thickness of Soil Layer 2(ft)
K1=Permeability of Layer 1 (ftIday)
K2=Permeability of Layer 2 (ftIday)

Figure 5: Soil Depth Profile

The entire thickness of the soil medium would be 1.73 feet after the top 12
inches of soil was removed, assuming a depth to groundwater of 2.4 feet as
determined earlier. As a result, the remaining top layer would be 5 inches of the
fine, sandy loam with the remaining bottom layer comprised of 11.8 inches of the
fine sand to coarse sand with some gravel. Using permeability values of 4
inches per hour and 20 inches per hour for the top and bottom layers,
respectively, the resulting mean value for the hvdraulic conductivity at the Rowe
Sanctuary site was 22.5 feet Der day. When combined with the value for aquifer
thickness, the transmissivity of the soil beneath the recharge site was found to
be 1710 ft21 day.
The second natural parameter required by CSUPAW was specific yield.
Specific yield is defined as the volume of water released from an unconfined
aquifer due to the drainage of voids by gravity. This is a dimensionless quantity
that is dependent on the geologic structure of the soil medium. A sDecific vield
of 0.254 was determined for the Rowe Sanctuary site based on an average of
the specific yield values listed in Table 2.5 of Groundwater Hvdroloov by D.K.
Todd(1980) for the soil types present at the site.
4.5 Recharge Basin Analysis
Using the previously defined natural model parameters, the analysis of
the recharge basin was performed using the CSUPAW model. The recharge

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