Surface Water Groundwater Interaction in San Acacia Reach

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Surface Water Groundwater Interaction in San
Acacia Reach

• Nabil Shafike
• New Mexico Interstate
• Stream Commission

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SW/GW A Single Resource
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Gaining / Losing Streams
Winter et al. 1998.
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Disconnected Stream
Winter et al. 1998.
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Stream Aquifer Interaction Under Stress
Winter et al. 1998.
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Mathematical Representation
Land Surface
If h gt RBOT Leakage Cond (HRIV h) If
h lt RBOT Leakage Cond (HRIV
RBOT) Riverbed Conductance KLW/M
Water Table
River Surface
Streambed
Stream aquifer System
Impermeable Walls
Head in Cell (h)
River Stage (HRIV)
MODFLOW River Packages - Riv1 (MODFLOW 83)
- Riv2 (Miller 1988) - Stream Pckg (Prudic,
89) - BRANCH (Swain et al, 97) - SFR-1 (Prudic
et al, 2004)
M
RBOT
W
Representation of the Stream aquifer System
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Conceptualization of the SW System
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Conceptualization of the Groundwater System
(Anderholm 1987)
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Shallow SW/GW Interaction
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Surface Water Depletion
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Rio Grande Seepage Analysis
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Aquifer Test Analysis
H. Hydrauic Conductivity (Kx) 72.0
ft/day V. Hydraulic Conductivity (Kz) 3.6
ft/day Kh Kz
20 1 Specific Yield (Sy)
0.15 Specific Storage (Ss)
6.0e-07 1/ft Discharge (Q)
76.0 gpm
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Regional GW/SW Model
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Riparian Vegetation
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Measured vs Simulated Steady StateWater Levels
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Simulated Steady State Water Levels
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Measured Water Levels at HW-380
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Measured Water Levels Near San Marcial
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Inflow Hydrograph at San Acacia(Transient Run)
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Riparian Evapotranspiration Rate
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Rio Grande Flow at San Marcial
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LFCC Flow at San Marcial
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Simulated Groundwater Levelsat Escandida and San
Antonio
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Operation Scenarios 1- Max diversion of 500 cfs
and min of 100 cfs 2- Max diversion of 1000 cfs
and min of 100 cfs 3- All flow diverted to LFCC
with a max of 2000 cfs Hydrology of year 2001
was used in all scenarios
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Water Budget Analysis
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Water Above Land Surface
Current Operation
Maximum Operation
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Concluding Remarks
For this specific year (2001-hydrology) and given
the model input conditions 1- SW Operations
impact its interaction with the groundwater
system. 2- There is no significant difference in
depletions between current operation of the LFCC
as a drain and a maximum diversion between 500
cfs to 1000 cfs. 2- Operating the LFCC up to
its maximum capacity (2000 cfs) provides the
most efficient way to convey water to Elephant
Butte because evapotranspiration losses are
reduced.