WATER SCIENCE Files

Spatial and Seasonal Variability of Base Flow in the Verde Valley, Central Arizona, 2007 and 2011

Synoptic base-flow surveys were conducted on streams in the Verde Valley, central Arizona, in June 2007 and February 2011 by the U.S. Geological Survey (USGS), in coopera- tion with the Verde River Basin Partnership, the Town of Clarkdale, and Yavapai County. These surveys, also known as seepage runs, measured streamflow under base-flow condi- tions at many locations over a short period of time. Surveys were conducted on a segment of the Verde River that flows through the Verde Valley, between USGS streamflow-gaging stations 09504000 and 09506000, a distance of 51 river miles. Data from the surveys were used to investigate the domi- nant controls on Verde River base flow, spatial variability in gaining and losing reaches, and the effects that human altera- tions have on base flow in the surface-water system. The most prominent human alterations in the Verde Valley are dozens of surface-water diversions from streams, including gravity-fed ditch diversions along the Verde River.
Base flow that entered the Verde River from the tributary streams of Oak Creek, Beaver Creek, and West Clear Creek was found to be a major source of base flow in the Verde River. Groundwater discharge directly into the Verde River near these three confluences also was an important contributor of base flow to the Verde River, particularly near the conflu- ence with Beaver Creek. An examination of individual reaches of the Verde River in the Verde Valley found three reaches (largely unaffected by ditch diversions) exhibiting a similar pattern: a small net groundwater discharge in February 2011 (12 cubic feet per second or less) and a small net streamflow loss in June 2007 (11 cubic feet per second or less). Two reaches heavily affected by ditch diversions were difficult to interpret because of the large number of confounding human factors. Possible lower and upper bounds of net groundwater flux were calculated for all reaches, including those heavily affected by ditches. View Document.

SRP Groundwater Flow Model for the Big Chino Valley

SRP consultants prepared a Big Chino groundwater flow model showing that groundwater pumping in the Big Chino would substantially diminish the Verde River. View Document.

Studies and Experts Agree: Withdrawing Groundwater from the Big Chino Valley Will Reduce Flow in the Verde River!

Understanding Arizona’s Riparian Areas

Report from the U of A Extension describing Arizona's riparian areas and their importance to the landscape. View Document.

USGS Publishes Verde Valley Seepage-Run Report

Substantially more water than necessary is diverted from the River during every growing season to support irrigation of farm fields, gardens, and lawns. Increased efficiency of the diversions and the irrigation they support will be essential to keeping more water in the river and protecting the Verde Valley's habitat and lifestyle. Published by the Verde River Basin Partnership. View Document.

Verde River Base Flow

Graph of base flow along the river from headwaters to Camp Verde taken from the Blasch report. View Document.

Verde River Basin Water Budget

Map of Verde Watershed showing flow volume, water source volume, water use volume, and land use. View Document.

Verde River Basin Water-Resources Primer

Verde River Basin Water-Resources Primer -- Understanding Our Water and Our Verde River Basin

The Verde River Basin Water-Resources Primer grew from a series of PowerPoint presentations given by retired U.S. Geological Survey geologist Ed Wolfe to Watershed Steward classes at the University of Arizona Cooperative Extension of Yavapai County.

The Primer provides well-explained, well-illustrated, documented source material for interested citizens, public decision makers, teachers, and presenters of water-resource information that is directed, in particular, to understanding the workings of the interconnected groundwater and surface-water systems of the Verde River Basin. 

View the document.

Chapter 1: Introduction

  The Richness of the Verde River

  Sources of Verde River Streamflow

  Is Year-Round Flow of the Verde River at Risk?

  Can We Sustain Our Treasured Verde River?

Chapter 2: The Global Water Cycle

Chapter 3: Groundwater

  Groundwater Recharge

  Aquifers and the Water Table

  Groundwater Movement

Chapter 4: A Hydrology Tool Box

  Water-Table Maps

  Characterizing Confined Aquifers, Potentiometric Surfaces, and Artesian Wells

  Applications of Geologic Observations and Wells for Monitoring and Evaluating Groundwater Resources

  Geologic Properties of Aquifer Rocks and Sedimentary Deposits

  Measurement of Hydraulic Heads within Aquifers

  Historic Records of Water-Level Change

  Aquifer Tests

  Groundwater Chemistry

  Streamflow Measurements

  Stream gage Measurements

  Seepage Runs

  Geophysical Tools

  Seismology

  Regional Gravity and Magnetic Surveys

  Precise Gravity Measurements for Storage-Change Analysis

  Numerical Groundwater Models

Chapter 5: Regional Hydrogeologic Framework in the Upper and Middle Verde River Watersheds

  Geologic Setting

  Regional Hydrologic Setting

  Alluvial Basins

  General Relation: Geology and Groundwater in the Upper and Middle Verde River Watersheds

Chapter 6: Occurrence and Flow of Groundwater and Surface Water in the Upper and Middle Verde River Watersheds

  What is a watershed?

  The Upper and Middle Verde River Watersheds and Their Administrative Groundwater Sub-basins

  Prescott Active Management Area

  Verde River Groundwater and Surface-Water Systems

  Groundwater Flow

  Base Flow along the Verde River

  Annual Streamflow, Base Flow, and Runoff along the Verde River

  Seasonality of Base Flow along the Verde River

  Irrigation Diversions

Chapter 7: Pumping and Its Effect on Groundwater and Streamflow In the Upper and Middle Verde River Watersheds

  Streamflow Depletion: A Consequence of Groundwater Pumping

  Streamflow Depletion in Action: Del Rio Springs, Little Chino Wash, Sullivan Lake, and the Uppermost Verde River

  Streamflow Depletion: Looking Ahead in the Verde Valley

  Potential Effects of Groundwater Pumping or Artificial Recharge on Streamflow and Groundwater-Dependent Vegetation in the Verde Valley

  Human Effect on Base Flow in the Verde Valley

  Change in Base Flow—1910 Through 2005

  Forward-Looking Simulations - 2006 Through 2109

Human Effect on Depth to Groundwater in the Verde Valley

  Conclusions and Inferences

Chapter 8. The Verde River Ecosystem – Riparian and Aquatic Habitat

  Native Fish in Arizona

  Verde River Plants and Animals

  Verde River Water Needs

  Riparian Trees and Groundwater

  Wetland Plants and Groundwater

  Native Wildlife

  Fish

  Finding Balance

Chapter 9: Perennial Flow of the Verde River: Is It At Risk?

  Potential Future Groundwater Demand in the Upper and Middle Verde Watersheds

  Potential New Water Demand in the Little Chino Sub-basin

  Potential New Water Demand in the Big Chino Sub-Basin

Potential New Water Demand in the Verde Valley Sub-basin

  Summary of Potential Water Demands In the Upper and Middle Verde River Watersheds

The Role of Pumping From Wells in Meeting Water Demand in the Upper and Middle Verde River Watersheds

  Eventual Effect of Capture from Past, Current, and Potential New Water Demands on Verde River Base Flow

  Groundwater Model Results—Extended effects of Past, Current and Future Groundwater Pumping

  Future Water Demand in the Verde River Basin and Its Relation to the Stream Gage Records

  What Might the Future Hold?

The Primer is in the public domain; please feel free to learn from it and draw on it in whatever way may be useful.

Water Commitments in the PrAMA and implications for the upper Verde and upper Agua Fria Rivers

The cities of Prescott, Prescott Valley, and the town of Chino Valley, commonly referred to as the Tri-Cities, currently rely almost exclusively on ground water from the Prescott Active Management Area (Prescott AMA) for their domestic water supply (fig.1). The Prescott AMA is also a source of water for agricultural use. At the present time, the AMA is being seriously over-pumped and has been for a number of years. Over-pumping has caused ground-water levels to continually decline in most of the Prescott AMA and has led to a continuing decline in the amount of water that naturally discharges from it to Del Rio Springs (water that once discharged to the upper Verde River), to the ground-water system of Big Chino Valley (which, in turn, discharges to the upper Verde River) and to the upper Agua Fria River. Ultimately, the amount of ground water that can be withdrawn from the Prescott AMA must be seriously reduced in order to be able to continue to withdraw water from it on a long-term continuing basis. Otherwise, someday, there will be no water.
By Ed Wolfe and William Meyer. View Document.

Water Resource Notes 3: Groundwater Flow Models

In order to make well-founded long-term water- management decisions that support a sustainable supply of groundwater for our grandchildren and their grandchildren and that ensure the year-round flow of a healthy Verde River, we need to have the best available scientific tools.
The Northern Arizona Regional Groundwater-Flow Model (NARGFM) is such a tool. It can be used to guide our elected officials and resource managers in developing water-management strategies that will protect the long-term health of our groundwater, springs, and perennially-flowing streams. View Document.

Well Hydrographs for the Prescott AMA

Annotated hydrographs throughout the Prescott AMA showing the change in water levels, by Doug McMillan. View Document.

Why Pumping the Big Chino Threatens the Verde River

Presentation slides by Ed Wolfe and Bill Meyer. View Document.