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<br />J. DEPARTMENT OP AGAICULTIIRE <br />. PAGE Z OP l <br />• <br />VA REPOVRCE6 CON6ERVATION SERVICE O6/1]/9B <br />1 <br /> WATER PEATURES <br />~ <br />te -- WATER FEATURES <br />:n <br />E~report gives estimates of various soil water Features. The set imatee are used in land use planning that involves <br />Bering considers[ lone. <br />iydrolo9it soil groups are used to estimate runoff from precipitation. Soils not protected by vegetation are <br />i~ned to one of four groups. They are grouped according to the infiltration of water when the voile are thoroughly <br />r nd receive precipitation from long-duration storms. The four hydrologic soil groups are: <br />' Group A•. Soils having a high infiltration rate (low <br />runoff potential) when thoroughly wet. These consist mainly <br />of deep, well drained to excessively drained sands or <br />gravelly sonde. Theee voile have a high rate of water <br />' tranemiee ion. <br />Group 'B^. Soils having a moderate infiltration rate when <br />thoroughly wet. Theee consist chiefly of moderately deep or <br />I deep, moderately well drained or well drained soils that <br />have moderately fine texture to moderately coarse texture. <br />Theee soils have a moderate rate of water tranamSseion. <br />' Croup •C•. So ila having a el ow infiltration rate when <br />thoroughly wet. Theee eoneiet chiefly of voile having a <br />layer that impedes the downward movement of water or voile <br />of moderately fine texture or fine texture. Theee soils <br />have a Blow rate of water tranemiesion. <br />Croup •D•. Soils having a very slow infiltration rate (high <br />runoff potential) when thoroughly wet. Theee cone fist <br />chiefly of clays that have a high shrink-swell potential, <br />soils [ha[ have a permanent high water [able, voile [hat <br />have a claypan or clay layer a[ or near the surface, and <br />' soils Chat are shallow over nearly imps rvioue material. <br />Theee soils have a very Blow raga of water eranemieeion. <br />'E~ soil Se assigned to two hydrologic groups in this report, the fire[ letter Se for drained areas and Che second <br />;e~or undra fined areas. Flooding, the temporary inundation of an area. Se caused by overflowing et reams, by runoff from <br />ant elopes, or by Cida e. water standing for short periods after rainfall or enowmelt fie not cone fide red <br />'.l ooding, nor Se water in swamps and marshes. This report gives the Frequency and duration of flooding and <br />;time of year when flooding fe moat likely. Frequency, duration, and probable dates of occurrence sae estimated. <br />uency fie expressed ae `None', `Rare', 'OCCaeional•, and 'Frequent`. `None' means that flooding Se not probable: <br />'Rare' chat it Se unlikely but possible under unusual weather conditions; •OCCae tonal' [hat it oc cure, on the <br />rage, once of lees in Z years; and 'Frequent` that it occurs, on the average, more Chan once in Z years. <br />bastion fie expressed ae 'Very brief' if lees Chan 2 days, `Brief` if 2 to ] days, 'Long' if ] to 3o days, and `Very <br />on Sf more Chan ]0 days. The information fie based on evidence in the soil profile, namely Chin et rata of gravel, <br />i silt, or clay depoe iced by floodwater; irregular decrease Sn organic matter content with Sncreae ing depth; <br />u~abaence of di atinct five horizons that form in voile that are not eubJect to flooding. Also cone idered are local <br />•.nEormation about the extent and levels of flooding and the relation of each soil on the landscape to historic floods. <br />J <br /> <br /> <br />