Soil Conservation

TIIMS Home > Basin Topics: Soil Conservation

Soil Conservation

Efforts Keeping the Lake Tahoe Basin´s Soil Underfoot

Soil conservation is essential for the maintenance of healthy plant communities, prevention of erosion, protection of water quality, maintenance of healthy stream systems, and protection of lake clarity. There are two major topics in soil conservation, impervious land coverage and stream environment zones (SEZs). Impervious land coverage like asphalt, concrete, and roofs do not allow water runoff from storms to sink into the ground, get filtered by the soil, and become groundwater. The excess runoff then overloads stream channels, eroding the banks and damaging vegetation. Stream channel erosion, transports nutrients and sediments to the Lake and reduces water clarity. SEZs are areas like meadows and marshes that slow water down by dispersing it over a large area and allowing sediment to settle out and nutrients to be taken up by vegetation. Although SEZ plant communities constitute a small portion of the Lake Tahoe Basin´s total vegetated land area, 11 percent, they are extremely valuable in providing habitat for wildlife , purification of water, and scenic enjoyment.

Since the late 1970s, regulatory agencies within the Lake Tahoe Basin, primarily Tahoe Regional Planning Agency (TRPA), have used the land capability classification system known as the “Bailey System” (Land-Capability Classification of the Lake Tahoe Basin, California-Nevada A Guide to Planning – Bailey, 1974) to evaluate applications that request either additional land coverage to existing developed lots or building permits for new development. In 1989, the “Individual Parcel Evaluation System” (IPES) replaced the Bailey System as the method for determining eligibility for building on vacant single-family residential parcels. Both of these programs were developed as erosion control techniques to mitigate the deleterious effects to stream systems and water quality that result from excessive land coverage. Together, the Bailey System and IPES restrict the amount of impervious land coverage on all parcels and generally prohibit new land coverage within areas classified as SEZs.

Regulations protecting the soil resource are enforced by TRPA, Lahontan Regional Water Quality Control Board, City of South Lake Tahoe, and Basin counties. The U.S. Forest Service, California Tahoe Conservancy, Nevada Division of State Lands, California State Parks, and Nevada State Parks are implementing soil conservation programs on their lands. Additionally, the USDA Natural Resources Conservation Service is in the process of updating the Soil Survey for the Tahoe Basin.

Other soil conservation measures employed in the Lake Tahoe Basin are the:

removal of excess land coverage followed by site restoration
implementation of Best Management Practices to minimize runoff and soil
protection of native vegetation, and
revegetation of disturbed lands.

Sources:

Draft TRPA 2003 EIP Update
Draft TRPA 2001 Threshold Evaluation Draft

See TIIMS Geology

Indicators

SC-1 Impervious Coverage

The TRPA Threshold for Soil Conservation requires that impervious coverage be in compliance with the coverage coefficients defined in the Land Capability Classification of the Lake Tahoe Basin California-Nevada, a Guide for Planning (Bailey, 1974). Additional land coverage is monitored on a project basis and recorded in square feet. Coverage may be utilized directly or by coverage transfers within a related project area. An excess coverage mitigation program is in place to gradually reduce existing land coverage.

SC- 2 Stream Environment Zone (SEZ)

TRPA policy requires the preservation of existing naturally functioning SEZ land in their natural hydrologic condition, the restoration of all disturbed SEZ lands in undeveloped, un-subdivided, lands and the restoration of the SEZ lands that have been identified as disturbed, developed or subdivided, to obtain a 5 percent total increase in the area of naturally functioning SEZ lands.

Click here for more information about soil conservation/SEZ indicators from the TRPA 2001 Threshold Evaluation

(Note: Large document may take a few minutes to download)

Research

A goal of TIIMS is housing documents about the past, present and future environmental research conducted in the Lake Tahoe Basin. Scientific research conducted by organizations, agencies, and universities aims to detect, for example, soil erosion and discover ways to monitor and ultimately eliminate environmental impacts. Ongoing research efforts collecting baseline data will help regulatory agencies establish regulations and develop limits and indicators designed to improve environmental health.

Agencies and institutions involved in soil conservation related research are: USDA Natural Resources Conservation Service, US Army Corps of Engineers, USDA Forest Service, US Geological Survey, University of California, Davis, University of Nevada, Reno, Desert Research Institute, Lahontan Regional Water Quality Control Board, and Tahoe Regional Planning Agency.

Soil conservation working groups have identified issues that drive implementation of research needed to meet the objectives of TRPA and other agencies. In addition, these groups, which strive to increase and maintain communication and collaboration among soil conservation interests in the Basin, also assist TRPA in identification of the current major issues confronting the soil conservation program. With assistance from the Science Advisory Group, TRPA is able to identify and direct limited funding to priority studies that will provide critical information to managers and policy makers.

TIIMS is always searching for more documents to include in this section so please contact tiims@trpa.org with possible links to other soil conservation research.

Impervious Coverage Resources

Bailey, R. 1974. Land-Capability Classification of the Lake Tahoe Basin, California-Nevada: A Guide to Planning. Forest Service, U.S. Department of Agriculture in cooperation with the Tahoe Regional Planning Agency. South Lake Tahoe, Calif.

Forney, W. et. al. 2001.Land Use Change and Effects on Water Quality and Ecosystem Health in the Lake Tahoe Basin, Nevada and California. U.S. Geological Survey, Open-File Report 01-418. Menlo Park, California.

Forney, W. et. al. 2002. Land Use Change and Effects on Water Quality and Ecosystem Health in the Lake Tahoe Basin, Nevada and California: Year-1 Progress. U.S. Geological Survey, Open-File Report 02-014.

Minor, T. and M. Cablk 2001.Analysis of Impervious Cover in the Lake Tahoe Basin Using Remote Sensing and Geographic Information Systems. Center for Watersheds and Environmental Sustainability, Desert Research Institute, University and Community College System of Nevada. Submitted to Tahoe Regional Planning Agency. January 2001. (EIP Project # 10162)

Murphy, D. and C. Knopp eds. 2000. Lake Tahoe Watershed Assessment: Volume I. Pacific Southwest Research Station, USDA Forest Service. General Technical Report PSW-GTR-175. (Chapter 4, page 252-261, “What is the evidence linking tributary sediment and nutrient loading to land use and watershed geomorphic characteristics”.)

USDA Soil Conservation Service and Forest Service 1974. Soil Survey: Tahoe Basin Area, California and Nevada. Prepared in cooperation with University of California Agricultural Experiment Station and the Nevada Agricultural Experiment Station. March 1974.

Stream Environment Zone Resources

Butt, A., M. Ayers, S. Swanson, and P. Tueller 1998. Lake Tahoe Basin Assessment for Restoration of Riparian Ecosystems. Report to the California Tahoe Conservancy. 60p.

California Tahoe Conservancy 2003. Lake Tahoe Basin Riparian Assessment.

Herbst, D. 2001. Biomonitoring on the Upper Truckee River Using Aquatic Macroinvertebrates: Watershed Restoration Baseline Data for 1998-2000. Sierra Nevada Aquatic Research Laboratory, University of California, Mammoth Lakes, CA. Submitted to Lahontan Regional Water Quality Control Board. December 2001.

Huffman & Associates, Inc. 1998. Draft Report of a Classification System for Stream Environment Zones within the Lake Tahoe Basin, Nevada and California. January 1998.

Huffman & Associates, Inc. 1998. Condition Assessment Handbook for Stream Environment Zones at Lake Tahoe, California and Nevada. Funded through U.S. Environmental Protection Agency, Region 9, Wetlands Protection and Restoration Program (USEPA 104(B)3 CD-999217-01-1). Prepared in conjunction with The Tahoe Regional Planning Agency. Zephyr Cove, NV. June 1998.

Lindstrom, S 2000. A Contextual Overview of Human Land Use and Environmental Conditions. Chapter Two, In: Murphy, D. and C. Knopp, eds. 2000. Lake Tahoe Watershed Assessment: Volume I. Pacific Southwest Research Station, USDA Forest Service. General Technical Report PSW-GTR-175.

Murphy, D. and C. Knopp, eds. 2000. Lake Tahoe Watershed Assessment: Volume I. Pacific Southwest Research Station, USDA Forest Service. General Technical Report PSW-GTR-175. (Chapter 5, pages 497 – 522, “What are some of the most ecologically unique and biologically intact environments and areas in the basin, and what is the state of knowledge about these areas?”, page 522, “What data gaps were revealed in the process of assessing ecologically significant areas?”, pages 522 – 526, “What monitoring, conservation, and research activities are most appropriate for the ecologically significant areas identified?”)

Simon, A., E. Langendon, R. Bingner, R. Wells, A. Heins, N. Jokay, and I. Jaramillo 2003. Draft Final Lake Tahoe Basin Framework Implementation Study: Sediment Loadings and Channel Erosion. USDA-Agricultural Research Service, Channel and Watershed Process Research Unit, National Sedimentation Laboratory, Oxford, Mississippi. July 2003. (Chapter 4, Channel Erosion and Basin Geomorphology)

Tahoe Regional Planning Agency 1977. Stream Environment Zones and Related Hydrologic Areas of the Lake Tahoe Basin: Importance, Encroachment, Preservation, Inventory Example. January 1977.