SDCP desert scene  - Illustration by Bill Singleton
SDCP
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A Vision For Riparian Protection

Riparian areas in a desert environment are vital places. Although sixty to seventy-five percent of all species in Arizona rely on a riparian environment at some point during their life cycle, a number of streams and springs in and near Tucson have ceased to flow year round or are affected by a lower water table. Our streams and springs need protection as well as restoration.

Riparian scene - Illustration by Bill Singleton

Riparian Protection

Riparian resources and aquatic systems are the most vulnerable and least protected habitats in Pima County.

Two years of review and research during the Sonoran Desert Conservation Plan process have added greatly to Pima County, Arizona’s understanding of its riparian resources. In addition, previously unknown perennial and intermittent streams and springs have been identified.

Threats to Riparian Systems
It is now known that there are more threats to riparian systems than the obvious ones. The impact is evident when a housing development destroys a creek or stream environment. However, the decline in groundwater from pumping or the spread of invasive non-native species may be less obvious, but may actually destroy as much or more riparian habitat.

Making Up for Lost Ground
While it is far too late to restore many of our riparian communities to their natural condition, the Sonoran Desert Conservation Plan proposes that other natural riparian systems be preserved, restored, and managed to compensate for decades of largely unintended destruction of these systems.

Protection Yields Benefits
The Sonoran Desert Conservation Plan validates Pima County’s previous investments in protecting riparian areas such as Cienega Creek, Tanque Verde Wash, the San Pedro River, and Sabino-Bear Canyon. The Plan has identified additional areas for protection. This action will not only protect wildlife and plants, but will also maintain recreational trails, promote groundwater recharge, protect water quality, and attenuate flooding.

High Impact to Urban Streams
Low elevation, valley-floor streams in eastern Pima County have been disproportionately affected by loss of water, loss of native species, and other problems. Today we have the opportunity to recreate some urban riparian systems using renewable sources of water which will in turn provide urban revitalization, recreation, and park development. The most benefit to the urban area will result from repairing the degraded riparian environments of our major drainage systems – the Santa Cruz, Rillito, and Pantano rivers and washes – and by enhancing protection of the remaining riparian fragments along their tributaries.

The Science and Technical Advisory Team adopted specific ecosystem function goals for the management and conservation of riparian areas. Major watersheds were identified and used as planning units. To the extent possible, the connection should be maintained or restored between interdependent components of river systems within a watershed such as the channel, overbank, floodplain, distributary flow zones, riparian vegetation, and connected shallow groundwater.
The appropriate management of uplands within each watershed will protect the dynamics of riparian and aquatic ecosystems. Sources of pollution that impact our river systems must be identified and managed to maintain water quality at a level that will meet the biological goals of the Sonoran Desert Conservation Plan. Sufficient in-stream flows must be ensured to achieve and protect the natural functions of riparian and aquatic ecosystems.

Priorities for Protection
The Science and Technical Advisory Team also established priorities for determining which areas should be protected. Protecting self-sustaining riparian and aquatic ecosystems that already exist is preferable to the creation of new or enhanced areas of riparian and aquatic life that depend on continual artificial inputs of water, energy, and materials. Priority is placed on the substitution of renewable water supplies for groundwater and surface water in areas where high-quality aquatic and riparian ecosystems still exist and where the diversion of water stresses those systems.

Priority Resources
The selected Priority Riparian Resources include:
• Rincon Creek, Cienega Creek, Arivaca Creek, Brown Canyon, Wakefield, Sutherland, Happy Valley, and portions of the San Pedro River which offer the greatest potential to protect valuable riparian habitat adjacent to existing natural preserves.
• Opportunities to add new riparian acquisitions to a larger landscape with existing uplands exist along Davidson Canyon, Gardner Canyon, Madera Canyon, Agua Verde Wash, and Sopori/Papalote Wash.
• Sonoran cottonwood-willow forests should be protected, 37 percent of which are located outside existing natural preserves.
Several restoration projects have been completed and more are in the process of being planned. Riparian restoration feasibility studies currently underway include:
• Rio Antiguo Restoration in conjunction with the Army Corps of Engineers.
• Paseo de las Iglesias in conjunction with the City of Tucson and the Army Corps of Engineers
• Tres Rios del Norte in conjunction with the Town of Marana and the City of Tucson.

 

native fishes  - Illustration by Bill Singleton & George Maleski

Evaluation Process
Many peer-reviewed studies were used to identify and evaluate the condition of, threats to, and opportunities for preserving and restoring riparian ecosystems in Pima County. Pima County staff and other experts mapped riparian areas outside the Tohono O’odham Nation and evaluated the availability of natural surface and groundwater supplies that sustain them.
“ Gap analysis” revealed that some of the largest and most important riparian areas lie outside existing reserves. Studies of existing reserves have shown us that land protection does not address issues such as groundwater depletion and habitat loss due to non-native species.
Studies prepared for the Sonoran Desert Conservation Plan indicated that many of our urban waterways are still quite wild and closely linked to the mountain canyon “refugia” for native aquatic animals. Urban development and restoration efforts, therefore, must include considering the impacts and benefits to native plants and animals and the ecological processes that sustain them.

Conservation Stategies
The Pima County Comprehensive Land Use Plan was developed in concert with the Sonoran Desert Conservation Plan. It includes guidelines to conserve 95 percent of the riparian areas that will be affected by development.
Pima County will integrate water and land use planning in order to protect and restore riparian areas. Land and water rights acquisition and partnerships with other government and private entities will also be used.
Conservation easements, zoning revisions, species re-establishment, control measures for non-native species, and riparian restoration are other strategies that have been or will be implemented to effectively protect riparian areas.
Water must be made available to riparian areas that are to be restored. An agreement with the City of Tucson permanently secures a minimum of 5,000 acre-feet of treated effluent per year for riparian restoration. The amount will rise to 10,000 acre-feet in 2005 and successive years.
Other sources of water are being considered and include treated effluent from Pima County wastewater facilities, stormwater runoff harvested from project sites, water rights acquired from previous uses such as agriculture and mining, and water from groundwater remediation projects.

Riparian Resources Map (PDF)

Riparian Protection and  Restoration Element: Adopted Goal Statements

La Corua - A Sonoran Tradition

 

SDCP - link to home page
Sonoran Desert Conservation Plan
Pima County Administrator’s Office
130 West Congress, 10th Floor
Tucson, AZ 85701
520-724-6460

 

Sonoran Desert Conservation Plan Home pima.gov