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through a fire hose containing a PVC end piece • . p and released Into the SVT. The PVC end piece will be covered by a 0.25 -inch mesh screen to prevent • p entrapment of aquatic biota greater than 0.25 inches in diameter. Acquired sediment will ' b e contained within the SVT and purified water will be returned to the river via an outlet tlet fire hose. Acquired sediment will be removed to an offsite disposal area. The volume of slit and water to be released is not yet known at this time. The City of San Marcos will measure sure the appropriate parameters during the initial silt removal event and quantity the report p q ty to the USFWS. The installation of sediment control measures such as retention pools throughout the study area will decrease inflow of sediment into the San Marcos River. However, due to the time constraints associated with the silt removal process, this project ' . p i p � will remain a tang -term operation and maintenance measure. Removal of all sedimentation sites from om City Park downstream to Rio Vista Dam is estimated to take approximately . pp ately 6 months to complete. Most areas will accumulate new sediment bars b the time the divers avers finish all designated sites. Upon completion of all sites, the process will begin again. g g (5) Riverbank Widening: Near the Hopkins Street crossing, p g, the river has become increasingly constricted as a result of widening stands of ear elephant (Enclosure 7, Photo 5). T p The infestation of elephant ear has decreased river flows allows - rig sediment to deposit into the plant stand. As a result, the elephant ear and deposited sediment meat continue to spread further into the river. Sail will be dredged from an approximate 1.0 acre area down to the base riverbed level from the existing elephant ear stands to widen both sides of the riverbank. ank. Approximately 30,000 cubic feet of dredged material will be removed from the site. A on - e foot strip of elephant ear will be left along the edge of the stand to minimize riverbank erns' ' ' ion and lass of silt into the river. The remaining strip of elephant ear and an o soil area ' y en p s remaining after the dredging operation will be re- vegetated with natives such as elbow w bush, coralberry, deer mutely, black willow and bald cypress. All dredged material will be removed from the study area and disposed of at an offsite landfill area. Benefits associated with the riverbank widening measure include reduction in deposited sediment and exotic elephant ear, increased recreational opportunities, � Pp s, restored river flows and increased available habitat for native plant and . animals ecies(OMIT PROJE p CT) (6) Debris & Hardpan Removal: Concrete debris drainage gutters ' g gu and a building foundation will be removed from various locations within the study area. An approximate 100-foot concrete -lined gutter is located in City ark on the eastern bank nk a f the San Marcos Raver (Enclosure 7, Photo 13). The concrete -lined gutter currently drains surface runoff from an automobile parking lot straight into the San Marcos River. The concrete will be removed and replaced with a grass -lined vegetative channel or geotextile rids. Because of the steep slope, the channel will need to be terraced or bermed to decrease water flow and subsequent soil erosion. The existing channel may also be widened to retain surface runoff longer and promote soil deposition. In addition, approximately 90 cubic feet of concrete will be removed from within the San Marcos River below the concrete -lined g utter. Concrete soil stabilization walls will be removed from two locations within the study area. The first site is located along the west bank of the San Marcos River `us � t south of the footbridge at City Park. Approximately 450 cubic feet of concrete will be removed from the rei