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from a passive- use county park to the south . Although less than the established 350-ft program optimum , these setbacks provide adequate separation , given the intended uses of the adjacent properties . Third , basin construction must minimally impact sensitive on-site habitats , most notably the wetlands that comprise most of the site ' s eastern one-half. As shown in Figure 2 .2 , the containment dike ' s outside toe lies a minimum of 50 ft from the nearest wetland edge along the basin ' s eastern side and at its northeast corner . However, establishing a similar setback was impossible in the central portion of the basin ' s western side where construction will impact up to 0 . 10 acres of disturbed wetland . Classified as a mixed wetland/Brazilian pepper community, this former hammock area now qualifies as predominantly wetland, based on hydric soils and periodic standing water. However, the dominant vegetation does not support this classification as previous clearing has promoted a dense regrowth of Brazilian pepper. Within the disturbed wetland, a formal wetland delineation would likely classify some isolated areas as upland . Avoiding this area and providing an appropriate dike setback would unduly constrain the basin ' s total area. Notably, the extensive mangrove impoundments within the site ' s eastern one- half offer ample opportunity for on- site mitigation . Fourth , because of low upland elevations, the likelihood of a seasonally high water table, and the possibility of a shallow limestone strata in portions of the site, basin construction must minimize the excavation depth necessary to obtain the required dike material . Qualitative information presented in the county soil survey (Wettstein et al . , 1987) provides the only available data describing soil and groundwater conditions on site . Native soils include ( in order of decreasing areal coverage) McKee mucky clay loam , Riomar clay loam , Jupiter fine sand, Chobee loamy fine sand, and Perrine Variant loamy fine sand . Characteristic of mangrove islands and swamps and thus confined to the wetlands within the site ' s eastern one-half, the McKee mucky clay loam and the Riomar clay loam soils avoid all construction impacts. The site ' s western one-half, predominantly upland and including those areas historically planted in citrus, contain the remaining three soil associations . Typical of low, broad flats , depressions , or poorly-defined drainways , all three upland soils are characterized as nearly level and poorly- drained to very poorly-drained . All three soils typically maintain a water table within 10 in . of the soil surface from four to more than six months each year. Because of the poorly-drained conditions, these soils become suitable for citrus production only if a water control system (e . g. , ditching and bedding) maintains the water table at a depth of 4 ft or greater . Relic evidence of such water control methods remains in portions of the former grove areas of Site IR- 14 . Notably, 7