Nitrate and Sediment Fluxes from a California Rangeland Watershed

Long-term water quality records for assessing natural variability, impact of management, and that guide regulatory processes to safeguard water resources are rare for California oak woodland rangelands. This study presents a 20-yr record (1981-2000) of nitrate-nitrogen (NO3-N) and suspended sediment export from a typical, grazed oak woodland watershed (103 ha) in the northern Sierra Nevada foothills of California. Mean annual precipitation over the 20-yr period was 734 mm yr(-1) (range 366-1205 mm yr(-1)). Mean annual stream flow was 353 mm y(-1) (range 87-848 mm yr(-1)). Average annual stream flow was 48.1 +/- 16% of precipitation. Mean annual NO3-N export was 1.6 kg ha(-1) yr(-1) (range 0.18-3.6 kg ha(-1) yr(-1)). Annual NO3-N export significantly (P < 0.05) increased with increasing annual stream flow and precipitation. Mean daily NO3-N export was 0.004 kg ha(-1) d(-1) (range 10(-5) to 0.55 kg ha(-1) d(-1)). Mean annual suspended sediment export was 198 kg ha(-1) yr(-1) (range 23-479 kg ha(-1) yr(-1)). There was a positive relationship (P < 0.05) between annual suspended sediment export, annual stream How and precipitation. Mean daily suspended sediment export was 0.54 kg ha(-1) d(-1) (range 10(-4) to 155 kg ha(-1) d(-1)). Virtually no sediment was exported during the dry season. The large variation in daily and annual fluxes highlights the necessity of using long-term records to establish quantitative water quality targets for rangelands and demonstrates the difficulty of designing a water quality monitoring program for these ecosystems

Arizona department of water resources: Securing Arizona's water future

The Arizona Department of Water Resources works to secure long-term dependable water supplies for Arizona's communities. The Department: administers and enforces Arizona's groundwater code, and surface water rights laws (except those related to water quality); negotiates with external political entities to protect Arizona's Colorado River water supply; oversees the use of surface and groundwater resources under state jurisdiction, and represents Arizona in discussions of water rights with the federal government. In addition, the Department explores methods of augmenting water supplies to meet future demands, and develops policies that promote conservation and equitable distribution of water. The Department also inspects dams and participates in flood control planning to prevent property damage, personal injury, and loss of life. In support of these activities, ADWR collects and analyzes data on water levels and on water-quality characteristics. Other responsibilities include management of floodplains and non-federal dams to reduce loss of life and damage to property. ADWR is not a municipal water provider

Results of ground-water, surface-water, and water-quality monitoring, Black Mesa area, northeastern Arizona, 1992-93 /

Shipping list no.: 96-0008-P.Includes bibliographical references (p. 36-37).Mode of access: Internet

Ground-water, surface-water, and water-chemistry data, Black Mesa area, northeastern Arizona, 2000-2001, and performance and sensitivity of the 1988 USGS numerical model of the N aquifer /

Includes bibliographical references (p. 73-75).Mode of access: Internet