Tamarack Project Background Information

• Description: Background on Tamarack Project inclduing notes, scopes of work, maps, meeting agendas and attendance records, and others.
• State: CO
• Basin: South Platte
• Water Division: 1
• Author: Various
• Title: Background on Tamarack Project related
• Water Supply Pro - Doc Type: Project Overview

Even though not used to estimate the conductivity of the sloughbed, the
observation wells located between the slough and South Platte River provide hints about
the degree of surface water /groundwater interaction at Tamarack. The drawdown
response in the observation well C15WS, located 15 in from the slough on the opposite
side from the pumping well, is shown in Table 4. This observation well experiences
declines in water level proving that the slough channel does not fully penetrate
throughout the saturated thickness of the alluvial aquifer and that some percentage of the
aquifer stress is being satisfied by flow from the aquifer on the non - pumping well side of
the slough channel. Water levels in observation well D135WS, located 135 in from the
slough on the side opposite of the pumping well, decline by approximately 0.1 in during
the entire 24 -hour period. Water levels observed in observation well E16SPR decline by
less than 0.01 in after the first ten to thirty minutes, suggesting that the pumping well
does not influence the South Platte River during the first 24 -hours of pumping. It is
hypothesized that additional pumping could influence both the slough channel and South
Platte River significantly, depleting both the slough channel and South Platte River to
satisfy the aquifer stress created by pumping.
Table 4 — Measured drawdown response in observation well C15WS, located on the
non - pumping well side of the slough channel, during stream/aquifer analysis test.
Elapsed Time (min) Drawdown (m)
0.00 0.000
24.67,
0.037
35.75
0.043
53.92
0.046
58.43
0.049
90.37
0.058
105.25
0.064
138.72
0.067
185.80
0.075
608.85
0.122
1096.92
0.183
1258.45
0.201
1333.45
0.207
1446.72
0.216
The water level transect from the pumping well, through the slough channel, and
outward to the South Platte River at the end of the stream/aquifer analysis test is shown in
Figure 8. The initial water level along this same transect, as presented in Figure 5, is also
shown to depict the influence of the pumping well on the slough/river /aquifer interaction.
Groundwater abstraction creates a significantly different water level profile, converting
the slough channel from initially a discharge zone to a source of water to satisfy the
12