Hualapai Valley Hydrologic Model: Presentation Date: 10/19/2020

Hualapai Valley Hydrologic Model

Jake Knight & Jamie Macy
Arizona Water Science Center

Problem

Expanding groundwater withdrawals in Hualapai Basin could impactthe City of Kingman, AZ municipal water supply

Objective

Assess impacts from additional groundwater withdrawals and enhanced recharge in Hualapai Basin

Approach

Groundwater Monitoring
Groundwater Modeling

Setting and Previous USGS Studies

Prior to ADWR Rural Watershed Initiative Program there was very little information known about Hualapai, Detrital, and Sacramento Basins

USGS studies from 2007-2013 laid the foundation

Changes in groundwater levels over time
Groundwater withdrawals within each basin
The geometry of the basins and subbasins
The basin characteristics – types of sediments and location
The water budget
A preliminary numerical model

Groundwater Monitoring

4 Groundwater monitoring locations based on GW model sensitivity analysis

Gravity Monitoring

Model Purpose and Forecast Strategy

The purpose of HVHM is to forecast the potential effects of groundwater withdrawals and enhanced recharge in the Hualapai Valley Basin, based on scenarios provided by Mohave County.
Forecasted conditions are intended to be conservative with regard to uncertainty.
Model development decisions were driven by the model purpose.
The end product is a mixture of simplicity and complexity. The model grid, stress inputs, and time discretization scheme are relatively simple, while the parameterization scheme is highly detailed.

Future Withdrawal Scenario

USGS and ADWR Withdrawal Scenario Comparison

USGS scenario = 128,800 acre-ft/yr (Mohave County developed scenario)
USGS max 44,000 acres in production
ADWR scenario A = 280,000 acre-ft/yr
ADWR scenario B = 340,000 acre-ft/yr
ADWR max 57,000 acres in production

Future Withdrawal PLUS Enhanced Recharge Scenario

Map ID	Project Name	Existing (ac-ft/yr)	Planned (ac-ft/yr)
1	Kingman treated wastewater recharge	1,200
2	Kingman Monsoon Park at Southern & Eastern Ave	10
3	Kingman Southern Vista & Hualapai Shadows subdivisions storm water basins		109
4	Kingman Hualapai Foothill subdivision washes		82
5	Kingman Rancho Satna Fe washes		50
6	Kingman SE area BLM Lan infiltration basins		178
7	Kingman Rattlesnake Wash infiltration basins		510
8	Kingman West area infiltration basins		93
9	Peacock Nuts LLC Property basins (8 basins)		1,693
10	Bank Street, High School infiltration project		200
11	Mohave Wash N of Thompson Ave basin and recharge well
Total		1,210	3,915

Model Simulations

Snapshots of Model Results

2020

2040

2060

2080

Dry Model Cells in Context

Kingman Subbasin Timing

ADWR

Scenario A below 1,200 ft bls in 2080
Scenario B below 1,200 ft bls in 2078

USGS

Scenarios simulate 650-725 ft bls near Kingman supply wells in 2050
Scenarios simulate 750-850 ft bls near Kingman supply wells in 2080

Forecast Results

Hualapai Subbasin Timing

ADWR

Scenario A below 1,200 ft bls in 2098
Scenario B below 1,200 ft bls in 2090

USGS

Scenarios simulate 550-625 ft bls in 2050
Scenarios simulate 650-725 ft bls in 2080

Model Summary

Groundwater to wells overwhelmingly from storage - mining

Timing, location, & magnitude of increased pumping most important aspects controlling forecasts

Kingman and Hualapai Subbasins will become less hydraulically connected, potentially totally disconnected. Monitoring important.

Model cells representing thinnest basin-fill material on perimeter of basin go dry in model simulations, but these areas are not the focus of the model forecasts.

Model projections show groundwater available at municipal supply wells beyond 2080