05/08/1995 Council Packet - Laserfiche WebLink

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Memorandum Page 2 April 7, 1995 Watermain The nearest watermain service is located adjacent to the sewer on Fourth Avenue. A 12" trunk waternain has been extended to this location from the elevated tank located about 1,200 feet further south. This 12" main could be further extended to serve the proposed project area. The concept plan includes looping the main through the project area which is desirable from a water quality standpoint. About 90% of the proposed lots would be served from this looped system. The City would require that the waternain be extended to the west limit of the plat on Lilac Street to make it accessible for any future extension. Storm Sewers/Drainage The significant existing drainage features found on the project site consist of County Ditch 10 which runs west to east through the site, County Ditch 22 which flows south along the northeast border to its confluence with 10 near the west end of existing Thomas Street, and a wetland area concentrated in the northwest area of the site. Except for possible utility crossings beneath it, County Ditch 22 is left in its existing condition. Four lots are shown abutting 22 before its confluence with 10 and three lots after. That portion of County Ditch 10 which passes through the proposed site would be greatly affected by the project. Whereas this channel currently flows open, the concept proposes two culverts be installed, each about 340 feet in length. The areas upstream of the culverts would be used for ponding. Any alterations to this ditch must first be reviewed and approved by the governmental agencies with jurisdiciton over it including, but not limited to, the Rice Creek Watershed District. The location of two ponding areas centrally between the north/south roadways eliminates the need for lengthy overland drainage swales which become maintenance intensive. Great care must he taken prior to proposing any alteration to the existing ditch system to ensure that properties located upstream are not adversely affected. This would require close coordination with the Rice Creek Watershed District and City staff. Streets The internal streets shown in the concept plan provide for 60 -foot rights-of-way as required by the City. The orientaiton of the roadways around the existing farmhouse area allows the development in that area to be isolated and delayed until future phases if desired by Mr. Behm. The roadway locations also indicate that existing wetlands and drainageways were certain design factors. The proposed concept assumes that an extension of Thomas Street to the west, across County Ditch 22, will not take place. The vacation of the Thomas Street right-of-way in this area would be required. As the County Ditch exists as a significant barrier to a roadway extension from the east this is a reasonable assumption. The Concept Plan indicates a phase break for the roadway construction near the northern limit of the project area. Although temporary, this cul-de-sac length would be far in excess of City design standards.