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Upper
And Middle Verde
Introduction
The Verde River Watershed, and in particular areas along the Verde River,
with its pleasing climate, year-round water, beautiful and diverse landscapes,
and close proximity to nearby desert and mountain resources are attracting
people in ever increasing numbers. Without proper planning, Arizona is in danger
of losing enormous economic, aesthetic, and environmental benefits associated
with the Verde River and its tributaries and the riparian areas associated with
each.
The population of the major cities and towns within the Verde Watershed has
more than doubled in the last 20 years and is projected to more than double
again within the next 50 years.
Municipal water usage has increased by more than 39 percent over the last
eight years and at the present rate of growth will increase by more than 400
percent over the next 50 years. Land uses are changing as more farms and ranches
are subdivided and commercially developed directly affecting water usage. The
number of wells is increasing proportionally with the rapid increase in
urbanization, which will affect the volume of water available in the regional
aquifer.
Background
Many of Arizona’s rivers have been taken for granted lately by communities
that have been developed next to the rivers. People have diverted and pumped
water, built dams and channelized rivers, cut down trees for homes, fuel, and
cropland, mined sand and gravel, poured chemicals and waste into the rivers, and
recreated for more than a hundred years on the Verde River and its tributaries.
These types of land and water uses without long-range planning may eventually
result in dry riverbeds with no green vegetation, no fish or wildlife, no
recreation attraction, and reduced economic potential.
It is unclear whether the current demands for surface water and groundwater
within the Verde River Watershed have caused any significant impacts on baseflow
levels of the Verde River itself. Increasing water demands at the current rate
of population growth without long-term water resource planning, however, will
eventually impact the availability of both surface water and groundwater. The
Little Chino sub-basin of the Prescott AMA has experienced significant
groundwater declines in some areas and these declines have reduced flow in Del
Rio Springs. Similar effects on other springs could be seen in the future with
unplanned continued development.
Little is known about how much groundwater is actually in storage in many
areas of the Verde Watershed or about how water use in the Upper Verde may
affect the continued availability of water for the Verde Valley, which depends
on Verde River flows. These issues have caused a great deal of concern,
expressed by water users within the Upper and Middle Verde areas as well as by
downstream users of Verde River water, about the future availability and
reliability of surface water and groundwater within the Verde Watershed.
Watershed Area
The Verde is located in Central Arizona and covers parts of Yavapai, Coconino,
and Gila Counties. Included are the headwaters of the Verde River, Chino,
Williamson, and Verde Valleys, the East Verde River, the incorporated areas of
Prescott, and portions of the Cities of Payson and Flagstaff.
The Verde River basin covers approximately 5,500 square miles and is divided
into the Big Chino, Verde Valley, and Verde Canyon sub-basins.
Description
Physiographic Features
The Verde River Watershed encompasses an area that extends from the Coconino
Plateau in the north to the USGS gaging station on the Verde River below Tangle
Creek in the south, and from the Juniper and Santa Maria Mountains in the west
to the Mogollon Rim in the east.
Within the watershed area are the headwaters of the Verde River, Chino,
Williamson, and Verde Valleys, the East Verde River, and portions of the Cities
of Prescott, Payson, and Flagstaff. The Verde River is a tributary to the Salt
River and is part of the Colorado River System.
The total length of the Verde River in the study area, including the Big
Chino Wash and its tributaries from north of Interstate 40 near Seligman to the
USGS gaging station below the confluence with Tangle Creek is approximately 235
miles.
The total drainage of the study area is 5,501square miles. The elevation of
the area ranges from 2,029 feet above sea level at the Verde River gaging
station, 1.3 miles downstream from Tangle Creek and nine miles upstream from
Horseshoe Dam, to 12,633 feet above sea level at Humphreys Peak in the San
Francisco Mountains.
For purposes of this study, the Verde Watershed is divided into the Upper and
Middle Verde regions, with the division occurring at the USGS gaging station on
the Verde River near Paulden. The Upper Verde region encompasses the Williamson,
Big, and Little Chino Valleys.
The Middle Verde region encompasses everything downstream of the USGS gaging
station on the Verde River near Paulden to the USGS gaging station on the Verde
River below Tangle Creek. The primary area of concern in the Middle Verde region
is the Verde Valley.
The Big Chino Wash meanders through Chino Valley, which extends from
Interstate 40 near Seligman in the north to very near Prescott in the southeast.
The elevation of Chino Valley ranges from approximately 5,200 feet near Prescott
and Seligman to about 4,300 feet at Sullivan Lake. The portion of Chino Valley
within the Prescott AMA is known as the Little Chino Valley.
Chino Valley is bordered by the Juniper Mountains on the west, Santa Maria
Mountains on the southwest, Sierra Prieta Mountains and portions of the Bradshaw
Mountain Range on the south, and on the northeast by the Black Mesa. These
mountain ranges typically reach elevations of 7,000 feet or more above sea
level.
Two of the three primary tributaries feeding the Big Chino Wash originate in
the Juniper and Santa Maria Mountains. They are Walnut Creek and its tributary
Apache Creek and Williamson Valley Wash, which flows through Williamson Valley.
The other tributary to Big Chino Wash originates on the Coconino Plateau and is
known as Partridge Creek.
Big Chino Wash is dammed just south of Paulden to form Sullivan Lake. The
watercourse below Sullivan Lake is considered to be the headwaters of the Verde
River. The Verde River is perennial from just below Sullivan Lake to the end of
the study area (143 miles).
From the headwaters below Sullivan Lake to Clarkdale, the Verde River flows
through some very rugged and scenic country. Two major tributaries join the
Verde in this stretch of the river. They are the Granite and Sycamore Creeks.
Granite Creek and its two tributaries, Willow and Bannon Creeks, originate in
the mountainous areas south of Prescott. Dams have been constructed on all three
of these waterways to provide water to the City of Prescott and the Chino Valley
Irrigation District (CVID). The construction of these dams created Willow Creek
Reservoir, Upper and Lower Goldwater Lakes, and Watson Lake. Granite Creek flows
north through Chino Valley and joins the Verde River about three miles below
Sullivan Lake.
Sycamore Creek originates on the Coconino Plateau and joins the Verde River
downstream from Perkinsville. Sycamore Creek runs through some scenic canyons
and is protected mostly by the Sycamore Canyon Wilderness Area.
The area from Clarkdale to below Camp Verde is known as the Verde Valley.
This Valley ranges in elevation from approximately 3,542 feet at Clarkdale to
3,133 feet at Camp Verde. Historically, this area has been more densely
populated than other areas on the Verde River. The Black Hills bound the Verde
Valley to the south and west, which reach an elevation of 7,815 feet at Mingus
Mountain, and on the north and east by the Coconino Plateau and the Mogollon
Rim. The major tributaries that contribute to the Verde River in this region are
the Oak, Dry, Wet Beaver, and West Clear Creeks. All these waterways originate
either on the Coconino Plateau or the Mogollon Rim.
The mountains of the Coconino Plateau and the Mogollon Rim are generally
higher in elevation than other mountain ranges previously mentioned. The average
elevation of these mountains is between 7,000 and 8,000 feet with Humphreys Peak
in the San Francisco Mountains and Baker Butte on the Mogollon Rim reaching
elevations of 12,633 and 8,074 feet respectively. Because the Coconino Plateau
and Mogollon Rim are higher in elevation than other mountains, precipitation is
generally greater on the slopes of these areas. As a result, all tributaries
that originate on these slopes tend to carry more water for longer periods
throughout the year.
Downstream from Camp Verde, the Verde River again flows through some very
rugged country. Three primary tributaries flow into the Verde River in the
stretch below Camp Verde to below the mouth of Tangle Creek. The three
tributaries are Fossil Creek, East Verde River, and Tangle Creek. Fossil Creek
and the East Verde River originate from the Mogollon Rim. Tangle Creek
originates in the Black Hills.
Oak Creek and the East Verde River are both perennial throughout their entire
lengths.
Wet Beaver, West Clear, and Fossil Creeks are perennial for most of their
lengths and only become intermittent or ephemeral at their lower reaches. Some
of the other washes and creeks such as Sycamore, Dry Beaver, Walnut, and Apache
Creeks are perennial for specific reaches of their course.
Climate
Precipitation
Arizona has two seasons of the year when precipitation is especially common.
A wet season in winter usually between December and March and a wet season in
summer usually between July and September. In winter, large cyclonic storms
originate in the northern Pacific Ocean that may spread precipitation statewide.
This precipitation is normally gentle. In the Verde River watershed, much of it
may occur in the form of snow, especially at the higher elevations. These storms
can last a few days depositing a foot or more of snow over large portions of the
watershed. Orographic uplifting caused by the forced uplifting of air masses by
mountain ranges accounts for the increased amounts of precipitation along
mountain ranges.
Winter storms produce most of the usable surface water supply. Summer
precipitation occurs as a result of the seasonal shifting of the Intertropical
Convergence Zone (ITC); the area where trade winds converge. This shift of the
ITC brings Arizona under the influence of subtropical air masses. The influx of
warm, moist air usually from July through September is called monsoon. The
sources of this warm, moist air are primarily the Gulf of Mexico and the Sea of
Cortez. The percentage of annual precipitation resulting from monsoon rains is
normally highest in southeastern Arizona and decreases toward the northwestern
part of the State. In the central region of the State including the Verde River
watershed, the summer monsoon accounts for an increase in precipitation
primarily during July and August.
Summer precipitation is the result of convection; the rising of heated, less
dense, moisture-laden air that forms thunderstorms. These thunderstorms usually
form over mountains and result in isolated, often violent downpours. Water from
these downpours may cause short, sometimes hazardous runoff better known as
flash flooding.
Mean annual precipitation in the Verde River watershed ranges from 10 to 20
inches in the valleys and plateaus to more than 25 inches in the higher
mountains. On the windward (southern and western) side of the highest mountains
such as the San Francisco Peaks, precipitation exceeds 30 inches and in some
years may exceed 40 inches.
Temperature
Temperatures in Arizona vary greatly from season to season and from one area
of the State to another. These large variations in temperature result mainly
from differences in elevation. In summer, average temperatures change with
elevation uniformly throughout the state from the mid 90s at altitudes below 500
feet, to the high 50s at altitudes above 8,000 feet.
Latitude is also a factor in temperature differences, especially in winter
when stations in the northeastern part of the state are often ten degrees cooler
than those at a similar elevation in the southeastern part of the state. The
most pleasant months in Arizona are in fall and spring. Clear skies, little
precipitation, and large daily temperature changes characterize these months.
These large daily changes in temperature are caused by intense surface heating
during the day and radiational cooling at night. In late winter and spring it is
not unusual for a diurnal temperature range of 30ºF to 40ºF and sometimes
exceeding 50ºF.
In the Verde River Study area, most communities are located at elevations
between 3,000 and 5,200 feet in a climate that is generally quite pleasant
during the summer months. This is especially true for those communities located
above 5,000 feet in elevation. Daytime temperatures during the summer normally
range from the upper 80s to low 90s with occasional periods of low 100s
occurring during periods of clear skies and low humidity. Mean daily minimum and
maximum temperatures in winter generally range from the low 20s to mid 30s and
the low 50s to low 60s respectively.
Evapotranspiration
Moisture leaves the surface of the earth and bodies of water through the
processes of evaporation and transpiration. Direct evaporation from the Verde
Watershed study area ranges from 85 to 110 inches annually from a Class A pan
(Laboratory of Climatology, 1975).
Ordinarily only the upper 30 cm (1 foot) of soil is dried by evaporation in a
single dry season.
Plants draw the soil water into their systems through vast networks of tiny
roots. This soil water, after being carried upward through the trunk and
branches into the leaves, is discharged through leaf pores into the atmosphere
in the form of water vapor. This process is known as transpiration. The combined
loss by both processes is known as evapotranspiration. Factors such as time of
year, temperature, length of day, amount of sunlight received, humidity, and
wind velocity are all contributing factors to the evaporation process. The
amount and extent of vegetation cover and vegetation type, such as deciduous or
coniferous trees and phreatophytic or xerophytic plants, are factors that
contribute to the amount of transpiration.
In the Verde Valley Study area, the average annual potential
evapotranspiration rate for the frost-free period varies from 15 inches along
the Mogollon Rim in the northeastern part of the study area to 25 inches in the
Verde Valley. The estimated annual evapotranspiration for the Verde Valley from
the USGS gaging station on the Verde River near Paulden to below the USGS gaging
station on the East Verde River near Childs is approximately 35,000 acre-feet.
Additional Information
In 2000, the Arizona Department of Water Resources published the Verde River
Watershed Study, an exhaustive review of the the Upper and Middle Verde River
and surrounding lands. Copies of this study are available from the Department’s
Water
Resources Information Central. |
