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Map Unit Description: McKenna gravelly silt loam, 0 to 8 percent slopes —Snohomish County <br />Area, Washington <br />Snohomish County Area, Washington <br />32—McKenna gravelly silt loam, 0 to 8 percent slopes <br />Map Unit Setting <br />National map unit symbol. 2hyp <br />Elevation: 50 to 500 feet <br />Mean annual precipitation: 30 to 60 inches <br />Mean annual air temperature: 48 to 52 degrees F <br />Frost -free period. 150 to 180 days <br />Farmland classification: Prime farmland if drained <br />Map Unit Composition <br />Mckenna and similar soils: 85 percent <br />Minor components: 15 percent <br />Estimates are based on observations, descriptions, and transacts of <br />the mapunit. <br />Description of Mckenna <br />Setting <br />Landform: Drainageways, depressions <br />Parent material. Basal till <br />Typical profile <br />H1 - 0 to 8 inches: gravelly silt loam <br />H2 - 8 to 33 inches: gravelly silt loam <br />H3 - 33 to 60 inches: very gravelly sandy loam <br />Properties and qualities <br />Slope: 0 to 8 percent <br />Depth to restrictive feature: 20 to 40 inches to densic material <br />Natural drainage class: Poorly drained <br />Capacity of the most limiting layer to transmit water (Ksat): Very <br />low to moderately high (0.00 to 0.20 in/hr) <br />Depth to water table: About 0 to 6 inches <br />Frequency of flooding: None <br />Frequency of ponding: Frequent <br />Available water storage in profile: Low (about 4.9 inches) <br />Interpretive groups <br />Land capability classification (irrigated): None specified <br />Land capability classification (nonirrigated): 6w <br />Hydrologic Soil Group: D <br />Forage suitability group: Wet Soils (G002XN102WA) <br />Hydric soil rating: Yes <br />Minor Components <br />Norma, undrained <br />Percent of map unit: 5 percent <br />Landform: Depressions <br />Hydric soil rating. Yes <br />USDA Natural Resources Web Soil Survey 1/29/2019 <br />Conservation Service National Cooperative Soil Survey Page 1 of 2 <br />