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MATER MANAGEMENT Entlnote •- WTER MANAGEMENT ~i PAGE 2 OF 3 OB/8/00 This report gives information on the soil properties and site features that affect water management. The degree and kitd of soil limitations are given for pond reservoir areas; embankments, dikes and levees; and aquifer fed excavated ponds. the limitations are considered "Slight" if soil properties and site features are generally favorable for the indicated use and limitations are minor and are easily overcome; "Moderate" if soil properties or site features are not favorable for the indicated use and speti al planning, design, or maintenance is needed to overcome or minimize the limitations; and "Severe" of soil properties or site features are so unfavorable or so difficult to overcome that special design, significant increases in construction costs, and possibly increased maintenance are required. This report also gives for each soil the restrictive features that affect drainage, irrigation, terraces and tliversions, and grassed waterways POND RESERVOIR AREAS hold water behind a dam or embankment. Soils best suited to this use have low seepage potential in the upper 60 inches. The seepage potential is determined by the permeability of the soil and the depth to fractured bedrock or other permeable material. Excessive slope can affect the storage capacity of the reservoir area. EMBANKMENTS, DIKES, AND LEVEES are raised structures of soil material, generally less than 20 feet high, constructed to impound water or to protect land against overflow. In this report, the soils are rated as a source of material for embankment fill. The ratings apply to the soil mateei aL below the surface layer to a depth of about 5 feet. It is assumed that soil layers will be uniformly mixed and compacted during construction. The ratings do not indicate the ability of the natural soil to support an embankment. Soil properties to a depth even greater than the height of the embankment can affect performance and safety of the embankment. Generally, deeper onsite investigation is needed to determine these properties. Soil material in embankments must be resistant to seepage, piping, and erosion and have favorable compaction characteristics. Unfavorable features include less than 5 feet of suitable material erd a high content of stones or boulders, organic matter, or salts or sodium. A high water table affects the amount of usable material. It also affects trafficability. AOUI FER-FED excavated ponds are pits or dugouts that extend to a ground-water aquifer or [o a depth below a permanent water table. Excluded are ponds that are fed only by surface runoff and embankment ponds that impound water 3 feet or more above the original surface. Excavated ponds are affected by depth to a permanent water table, permeability of the aquifer, and quality of the water as inferred from the salinity of the soil. Depth to bedrock and the content of large stones affect the ease of excavation. .- DRAINAGE is [he removal of excess surface and Subsurface water from the soil. How easily end effectively the Soil is drained depends on the depth to bedrock, to a cemented pan, or to other layers that affect the rate of water movement; permeability; depth to a high water table or depth of standing water if the soil is subject to pording; slope; susceptibility [o flooding; subsidence of organic layers; and pot entiat frost action. Excavating and grading and the stability of ditchbanks are affected by depth to bedrock or to a cemented pan, large stones, slope, and the haxa rd of cutbanks caving. The productivity of the soil after drainage is adversely affected by extreme acidity or by toxic substances in the root zone, such as salts, sodium or sulfur. Availability of drainage outlets is not considered in the ratings.