1. Surface Water – Groundwater Interaction in San Acacia Reach
Nabil Shafike
New Mexico Interstate
Stream Commission

2. SW/GW A Single Resource

3. Gaining / Losing Streams
Winter et al

4. Disconnected Stream
Winter et al

5. Stream Aquifer Interaction Under Stress
Winter et al

6. Mathematical Representation
Land
Surface
If h > RBOT
Leakage = Cond (HRIV – h)
If h <= 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

7. Conceptualization of the SW System
Drain Unit 7
Rio Grande
Lemitar
1200
Neil Cupp
Waste Way
BDA Diversion
Irrigation System
Bosque del Apache NWR
San Marcial
San Acacia
Elephant Butte Reservoir
9 Mile outfall
Riparian System
LFC Channel
Socorro Main Canal
Storm Water

8. Conceptualization of the Groundwater System
(Anderholm 1987)

9. Shallow SW/GW Interaction

10. Surface Water Depletion

11. Rio Grande Seepage Analysis
Distance (mile)
Loss (cfs/mile) 10
9.5
6.5
3.5 12 4
1 to 4
5 to 10
13 to 20
5 to 12
4 to 10
2 to 10
1 to 2
San Acacia
Brown Arroyo
HW 380
North BdA
South BdA
San Marcial
Fort Craig
Escondida Br.

12. Aquifer Test Analysis H. Hydrauic Conductivity (Kx) = 72.0 ft/day
V. Hydraulic Conductivity (Kz) = ft/day
Kh : Kz = 20 : 1
Specific Yield (Sy) =
Specific Storage (Ss) = e-07 1/ft
Discharge (Q) = gpm

14. Regional GW/SW Model

15. Riparian Vegetation

16. Measured vs Simulated Steady State Water Levels

17. Simulated Steady State Water Levels

18. Measured Water Levels at HW-380

19. Measured Water Levels Near San Marcial

20. Inflow Hydrograph at San Acacia (Transient Run)

21. Riparian Evapotranspiration Rate

22. Rio Grande Flow at San Marcial

23. LFCC Flow at San Marcial

24. Simulated Groundwater Levels at Escandida and San Antonio

25. 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

26. Water Budget Analysis

27. Water Above Land Surface
Current Operation
Maximum Operation

28. 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.