An example: Xxxxx County Pond Sample Clauses

An example: Xxxxx County Pond. In November 2000 a flood test was performed at a stormwater infiltration pond in Xxxxx County, shown in Figure A.2. The pond is located in a residential area in the northern part of Vancouver, Washington. No information was available regarding the age of the pond or area of the basin that drains into the pond. The pond bottom is rectangular with dimensions 75 feet by 25 feet. The side slopes were surveyed to be 0.3 (V:H) and the depth of the pond is approximately six feet. A three-foot high retaining wall constructed with concrete blocks in located on the north side of the infiltration pond. The retaining wall is permeable because of open spaces between the concrete blocks. The water flows into the infiltration pond from a pre- treatment area located on the grassy plateau above the retaining wall. Stormwater discharges to the pretreatment area from two pipes located at opposite ends of the grassy plateau. The pond bottom and side slopes are covered with patches of xxxx and grass and two trees are located in opposite diagonal corners of the pond. The side slopes of the pond are covered in patches of grass. The basic data that were used to estimate infiltration rates at the Xxxxx County site are shown in Table A.1 and in Figure A.3. Table A.1 lists the flow rates, the duration of the test, and the pond geometry. Figure A.3 shows the depth of water as a function of time, measured at 10-minute intervals. The flow rate into the pond during the filling portion of the test was approximately 2000 ft3/hr (250 gpm) and the filling stage lasted for approximately 2.5 hours. The water level in the pond reached a depth of approximately 21 inches during the filling portion of the test. Table A.1 - Summary of data for full-scale infiltration tests.