Many producers within the District are adopting direct seeding systems. The District plans to assist these producers by providing both technical and financial assistance. The implementation of direct seeding systems will reduce erosion by an estimated 25%. Additional benefits include improved soil quality/health, reduction in fossil fuel consumption, improved carbon sequestration, increased water infiltration and improved watershed hydrology. The Camas Prairie region of the District has increased bluegrass for seed production by an estimated 30% in the past 5 years. Benefits are improved yields and improved agricultural sustainability. Over 700 acres of irrigated cropland is used primarily for the production of garden produce. Management challenges for irrigated producers include disease control, product marketing, erosion and loss of production, and limited water availability.
Pasture acres are generally located in close proximity to perennial streams and intermittent drainages. Livestock grazing has a direct influence on the riparian areas. Riparian areas adjacent to pastures with excessive livestock grazing use are degraded from lack of protective woody and perennial grass cover. Lack of protective vegetation along stream channels increases channel erosion during runoff events.
The majority of rangeland acres occur on steep canyon walls adjacent to perennial streams and intermittent drainages. Slopes range from 40 to 90 percent. Livestock grazing occurs predominantly in the spring and summer months. Some rangeland units are grazed for a twelve-month period.
Noxious weed invasions on rangeland have drastically reduced forage production. Aggressive weeds of concern include yellow starthistle and cheatgrass brome.
The severe soil limitations and low production potential of rangeland cause range improvement practices to be very costly, resulting in a small return on investment. Erosion concerns on rangeland are primarily ephemeral gully and stream bank erosion. Stream bank erosion may be a problem where livestock have direct access to streams for drinking water and crossings.
The Craig Mountain area has moderate to severe erosion problems caused by the building of roads and their maintenance. Erosion rates vary from 1 ton to 40 tons per acre. The most serious concern is sediment delivered to streams. Poor logging practices, insect infestations, and root and stem diseases are impacting forest health. Eighty percent of the forestland acres need some type of conservation treatment.
The Idaho Forest Practices Act (IFPA) provides for the application and inspection of BMPs on forestland. Forest management practices must meet or exceed the intent of the IFPA best management practices to comply with the state water quality standards.
Riparian areas are adjacent to water sources such as streams, springs, rivers, and ponds. A healthy riparian system provides sediment filtering, bank stabilization, water storage and release, and aquifer recharge.
The magnitude, duration and frequency of stream flow are the most important factors influencing riparian areas. Riparian systems are dynamic, and condition of vegetation on a site is only one attribute of riparian health. Riparian health should be evaluated in terms of physical and biological function in relation to the entire watershed (Gephardt, 1992).
It is unlikely that soil and water conditions at many riparian sites will remain stable. Erosion resistance is characterized by vegetation condition as it relates to soil and substrate stability and texture. Vulnerability of the area or susceptibility to change may be influenced by external activities. Riparian areas have been subject to extreme hydraulic events as well as intensive grazing and forest harvesting activities.
Wetlands are typically associated with Aquolls, Riverwash and Aquents, Bridgewater-Joseph, Wilkins silt loam, and Westlake-Latahco complex soil types. These soils are hydric because of saturation, are naturally supportive of woody vegetation, and are seasonally ponded or flooded. A wetland inventory was completed utilizing climatic data, soil survey information, and hydric soil lists coupled with the use of a geographic information system (GIS). Soils were categorized by landscape such as floodplain, terraces and drainage ways. The inventory showed approximately 7,000 acres of wetlands within the District. Many of the wetlands were historically drained. NRCS and Corps of Engineers policies and procedures for the protection of wetlands will be followed.
Other Land Uses and Management Needs
There are 602 miles of public roads in Nez Perce County.1 Of these miles, 200 are paved and 402 are unpaved. Roads have a significant impact on conservation planning considerations and are often major contributors to erosion.
The main conservation problems in urban and suburban areas are surface runoff, which causes sedimentation and water quality problems. Erosion from residential development and road building are concerns. Recreational activities include big game, upland bird and waterfowl hunting, fishing, rafting, boating, water-skiing, snowmobiling, hiking, camping, and cross-country skiing. All terrain vehicles have become very popular in areas that are inaccessible by road. This presents an erosion problem that can be serious. If vehicles are in constant use in repeated areas, grasses and plants that are necessary to hold the soil base are stripped away, and sedimentation occurs in adjacent streams and watercourses. Other visitors to the area are attracted to Hells Canyon National Recreational Area, located at the southern end of the county. In 1999, over 22,000 people toured Hells Canyon by commercial jet boat and over 350 people experienced the canyon via commercial rafting operations. In addition to this, twelve of these commercial outfitting businesses are located in Lewiston.2
1 Nez Perce County Road and Bridge Department, 2000
2 Unpublished correspondence with Michelle Peters, Director Hells Canyon Visitor Assoc., August 2000.