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In addition to the Hydraulic Ditch (canal) ther,~ are I:wo other canals which also traverse the entire basin. The northern-most canal which crosses the central part of the basin is a relatively small canal known as the Fruitland Ditch. As stated above, the Hydraulic Ditch, which is designed to transport approximately 96 cubic feet per second (CFS), crosses the basin south of Pear Street. The third canal known as the Oil Creek Ditch crosses the basin between US 50 and Arkansas River. Although most basin run-off is tributary to these canals, their capacities ar,: such that larger stonn flows will inundate the canals allowing water to flow over the existing canals. The western portion of the Orchard Avenue Drainage Basin traverses through a broad channel which has its origins in an undeveloped rangeland a.rea which currently contains the Police Firing Range. This upper reach of the basin contains several small natural swales which combine into a single, broad swale as it nears High Street. TIle channel crosses under High Street through a 50"x 31" corrugated metal pipe (CMP) and continues flowing south where it is joined by two other northerly channels which also crosses High Street via a 30" CMP and a 29"x 18" CMP. These channels cross over the Fruitland Ditch syphon approximately 800 feet north of South Street. The combined flow from approximately 550 acres continues flowing under South Street in a 60" CMP. From South Street to Central Avenue Ihe drainage course is a defmed channel which narrows to approximately 4 feet wide prior to crossing Central Avenue through a 48" eMP. The reach between Central A venue and Pear Street is a mere roadside ditch which is directed into 2- 30" CMP's. From this point the flow is direct,:d into the Hydraulic Ditch approximately 600 feet south of Pear Street. The central subbasins are also drained by natural swales in the upper reaches of the subbasins. As these channels approach developed areas, the broad swales narrow into extremely small developed channels. The reach between Ccntral Avenue ;md Pear Street must snake between existing houses in a small concrete channel while making two 90 degree bends. The flow from tillS channel is also intercepted by the Hydraulic Ditch. The easternmost subbasins flow through natural swales and roadside ditches, crossing Central Avenue and Pear Street in 18" CMP's. This flow appears to turn eastward and :flow into the Abbey Channel. Thc area south of the Hydraulic Ditch is drained by several north/south streets which all flow to US 50. This major roadway currently acts as a dam causing the stonn flow to ~ond along the roadway until it sheet flows across the pavement. The stonn flows which cross the highway and the Denver & Rio Grande Western Railroad continues south along sevcral street:;. 111e street flow is then intercepted by the Oil Creek Ditch. Once that canal overflows, the storrnwater will continue as sheet flow into the Arkansas River. The undersized culverts and lack of defined stornl system to carry flow directly w the Arkansas River has added to the threat of frcquent, shallow flooding to the residential neighborhoods north of US 50. The Hydraulic Ditch which is approximately 12 feet wide with an av,;rage slope of about 0.1 % is quickly oveIWhelmed by most stonnflows again directing flows toward the residential streets. C. Existing Surface Water Improvements The only significant surface water impoundment is located adjacent to the Arkansas River between 19th Street and Cottonwood A venue. The existing wetland pond is an old river ox bow fonned when the Arkansas River was channeled several year, ago. The current ponding area covers approximately 8 acres with direct flow into the river..