Hydrogeology and Simulated Effects of Future Water Use and Drought in the North Fork Red River Alluvial Aquifer: Progress Report

Transcription

1 Hydrogeology and Simulated Effects of Future Water Use and Drought in the North Fork Red River Alluvial Aquifer: Progress Report Developed in partnership with the Oklahoma Water Resources Board S. Jerrod Smith Derrick L. Wagner Christopher R. Neel USGS Oklahoma Water Science Center December 1, 2015

2 INTRODUCTION The OWRB needs a tool (model) to analyze water allocation management scenarios and effects. The information provided by this tool helps the OWRB determine a maximum annual yield and equal proportionate share for the aquifer. In Sept. 1981, the OWRB set a maximum annual yield and equal proportionate share (1 ac-ft/ac/yr) for the North Fork Red River alluvial aquifer based on a hydrologic investigation and Trescott groundwaterflow model by Kent (1980) and Paukstaitis (1981).

3 PROJECT OBJECTIVES Update the hydrologic investigation of the North Fork Red River alluvial aquifer with new data and analysis. Evaluate the effects of projected groundwater withdrawals and drought on aquifer storage and stream base flow. PROJECT SCOPE Alluvial aquifer of the North Fork Red River and major tributaries upstream from Tillman County: includes Elm Fork Red River and Sweetwater, Elk, and Otter Creeks Data collected through 2013

4 TASKS 1) Establish the hydrogeologic framework (including aquifer boundaries and flow properties). 2) Formulate a conceptual model. 3) Construct a groundwater-flow model to simulate alluvial aquifer system, ) Run predictive simulations. 5) Document results.

5 HYDROGEOLOGIC FRAMEWORK: determine boundaries and flow properties of geologic units Boundaries from geologic maps, DEMs, previous studies, OWRB permitted wells, OWRB lithologic logs, and limitations of model discretization. 1,500 drillers lithologic logs were standardized into basic lithologic categories (clay, silt, sand, and gravel) and used to distribute hydraulic conductivity values. Four Geoprobe Hydraulic Profiling Tool holes were completed in the alluvium saturated zone to characterize and constrain the valid range of hydraulic conductivity.

6 Geologic units: Quaternary alluvium Quaternary terrace/dune Tertiary Ogallala Fm. Permian shale/siltstone Cambrian igneous Site-specific lithology: OWRB lithologic logs Geoprobe HPT holes

7 MODEL HYDRAULIC PROPERTIES Alluvial aquifer hydraulic conductivity from: Geoprobe HPT OWRB lithologic logs Number of observations Number of observations >0 >4 >8 >12 >16 >20 >24 >28 >32 >36 >40 >44 >48 >52 >56 >60 >64 >68 >72 >76 >80 >84 >88 >92 >96 >100 Estimated hydraulic conductivity, in feet per day >0 >4 >8 >12 >16 >20 >24 >28 >32 >36 >40 >44 >48 >52 >56 >60 >64 >68 >72 >76 >80 >84 >88 >92 >96 >100 Estimated hydraulic conductivity, in feet per day Provisional data, subject to revision

8 CONCEPTUAL MODEL OF GROUNDWATER-FLOW SYSTEM 100,000 80, in (about 7 % of annual precipitation) Mean-annual flow, in acre-feet 60,000 40,000 20, ,000-40,000-60,000-80,000 3,000 87,000-60, cfs -16,000-15, in -100,000 Lakebed seepage Recharge Base flow to streams Discharge area ET and springs Groundwater pumping Budget category Provisional data, subject to revision

9 CONCEPTUAL MODEL OF GROUNDWATER-FLOW SYSTEM

10 GROUNDWATER PUMPING, IN Model period ACRE-FEET, % Monthly distribution (from OCWP) 40% Percent of annual demand 35% 30% 25% 20% 15% 10% Public Supply 5% 0% Irrigation JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Month Provisional data, subject to revision

11 OWRB depth to water, in feet, : Beckham County Greer County Kiowa County Provisional data, subject to revision

12 Continuous Water-Levels, April 2013 January 2015 Mesonet Daily Precipitation Provisional data, subject to revision

13 MODEL DISCRETIZATION: Stable transient model (MODFLOW 2005), discretized as: 1 steady-state stress period, and 408 transient stress periods (monthly), ; 2-layers: Alluvial aquifer and Permian bedrock 270-meter node spacing Active MODFLOW packages include: Recharge, Evapotranspiration, Well, Streamflow Routing, Gage ( , , ), Time-variant head (Tom Steed Reservoir), Lake (Lake Altus), Drain (springs)

14 Model Spatial Discretization Drains Wells Streams Gages Lake ET Head Obs Model Domain Provisional data, subject to revision

15 PRODUCTS AND TIMELINE A calibrated and reviewed transient model, A 50-year current-water-use scenario A 10-year drought scenario OWRB Equal-Proportionate Share scenarios determine the rate each well can withdraw while maintaining at least 5 feet of saturated thickness in 50% of the aquifer after a specified number of years A USGS Scientific Investigations Report (SIR) published by June 2016

16 Questions FOR MORE INFORMATION: S. Jerrod Smith Derrick L. Wagner Christopher R. Neel Kent, D.C., 1980, Evaluation of aquifer performance and water supply capabilities of alluvial and terrace deposits of the North Fork of the Red River in Beckham, Greer, Kiowa and Jackson Counties, Oklahoma. 132 p.