Forest Glen Recreation Residence Septic System Improvements Soils Report Shasta-Trinity National Forest January 2011

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1 Terrain Background: Soil map units: Forest Glen Recreation Residence Septic System Improvements Soils Report Shasta-Trinity National Forest January Deadwood very gravelly loam, 40 to 60% slopes 203 Neuns very gravelly loam, 20 to 40% slopes 204 Neuns very gravelly loam, 40 to 60% slopes 351 Xerofluvents-Riverwash complex, 0 to 20% slopes Generally, steeper areas are gravelly loam soils and flatter areas are very cobbly sandy loams and coarse sands (see figure 1). Figure 1 Forest Glen soils Most soils have good infiltration and drainage rates except map unit # 351 Xerofluvents- Riverwash which have very rapid infiltration and drainage rates that make them susceptible to excessive leaching. Septic leach fields in these areas will not function properly unless they are engineered raised bed systems. Neuns and Deadwood soils are susceptible to erosion without cover (all map units except 351). Most soils have more than adequate cover so erosion levels are at low levels. Shasta-Trinity National Forest - 1

2 Forest Glen cabins which are located along the South Fork of the Trinity River are mostly on slope colluvium (map unit 204) mixed with upper terrace alluvial soils which are forest loams (gravelly loams to clay loams or fine sandy loams to sandy clay loams) on 100- year flood river terraces. These soils have high chroma mottles below 40 inches (evidence of seasonal saturation) and no low chroma mottles observed (evidence of standing water). Site Investigation: Three recreation residence cabin sites were soil sampled to test site suitability for septic tank and leach line locations (see map below). Locations were gps ed, distances to terrace cut-bank measured, soil pits at each leach line were hand dug and described to 36 inches and augured below until stopped by cobbles at 40 to 50 inches deep. Cut-banks below septic leach lines were observed and described as to textures, clay %, and evidence of mottling below 40 inches (see table below). Figure 2 Forest Glen soils map and septic tank locations Table 1 Forest Glen soils data Forest Glen Recreation Residence Soil Investigation Data Rec. Res. Track # Soil Map Unit* Soil Textures Clay % Depth of Soil Depth to High Chroma Mottles#Distance to Cutbank Hansen inclusion Hugo gravelly loams 12 to 16 very deep 36 inches 90 feet Emerson inclusion Hugo gravelly loams 15 to 22 very deep 42 inches 50 feet Belifuss inclusion Neuns gravelly loams 15 to 28 very deep 52 inches 45 feet * These areas are slope colluvium that extended from soil map unit 204 on to 100 year flood plain of forest loams # Cut-banks were observed and measured for textures, clay %, depth of soil, and depth to mottling Shasta-Trinity National Forest - 2

3 Conclusion of site investigation shows adequate soil textures for proper sewage treatment and no standing water was observed with only high chroma mottling below 40 inches, showing seasonal saturation. Well-log data from F.S. Forest Glen rental cabin showed standing water at 24 feet with above textures of silty sands to gravelly forest silt sands. With seasonal use when soils are unsaturated, warmer and moist, effluent will be consumed by bacteria before late fall rains saturate soils. This was the conclusion of the Trinity County Environmental Health Division (see attached letter). Necessary Mitigations: Control of Effluent: Septic leach fields need to be in compliance with county regulations in regards to locations near water sources (South Fork Trinity River). Septic systems need current inspection reports to prove compliance with county regulations or upgraded to meet county requirements. Control of Erosion: Septic tank and leach line excavated material shall have erosion barriers placed around spoil to prevent erosion from occasional rain during construction. After completion of septic and leach line replacements excavated site shall be covered with appropriate mulch (needles, leaves, duff) to protect site from erosion. Conclusion: With the above design features there are negligible effects on soils and waters of California with this project. Shasta-Trinity National Forest - 3

4 Attachment: Shasta-Trinity National Forest - 4

5 Brad Rust Forest Soil Scientist ARCPAC Professional Soil Scientist Shasta-Trinity National Forest Headquarters, The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or part of an individual's income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) Persons with disabilities who require alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA's TARGET Center at (202) (voice and TDD). To file a complaint of discrimination, write to USDA, Director, Office of Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C , or call (800) (voice) or (202) (TDD). USDA is an equal opportunity provider and employer. Shasta-Trinity National Forest - 5