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HomeMy WebLinkAboutWATERFIELD PUD, FIRST FILING - FINAL - 7-95C - CORRESPONDENCE - STORMWATER-RELATED DOCUMENTS (3)Mr. Mike Ludwig Page 2 June 20, 1997 In addition, a chemical analysis of the irrigation canal water, ground water, and wetland pond water will be conducted. This analysis will help in determining the source of water for the wetlands. An analysis of the major ionic species (Ca, Mg, Na, K, Cl, HCO., and SO.) for the three waterbodies would provide sufficient information to determine water types. A trilinear diagram plot will graphically display the differing water compositions. Please do not hesitate to contact me if you have any questions concerning this letter or the future work planned for the Waterfield P.U.D. Site. Sincerely,. Riverside Technology �eG2r Z Terry Geiselman Registered Geologist cc: Rob Wilkinson, City of Fort Collins Basil Hamdan, City of Fort Collins Jim McCory, Colorado Land Source Bud Curtiss, Northern Engineering Patrick Plumley, RTi Richard Spotts, RTi generul/ludwig2.dnc (Wa?97 A) Riverside Technology, inc. Water Resources Engineering and Consulting June 20, 1997 Mr. Mike Ludwig Project Planner Fort Collins Planning Department 281 N. College Ave. Fort Collins, CO 80526 Dear Mr. Ludwig: This letter is in response to the Waterfield P.U.D. Fist Filing scheduled for June 18, 1997. It is Riverside Technology, inc.'s (RTi's) understanding that the Waterfield P.U.D. First Filing will consist of the apartment complexes and single family dwellings located on the property's east side. We also understand that the City wishes to avoid any impacts to the wetland area if possible. There is some concern because a subdrain system will have to be installed to allow for the construction of basements in the single family dwellings. The current plan is to route the water collected in the subdrain system to a detention area located to the southwest of the property. If the diverted water is currently supplementing the wetland hydrology, the reduction in ground water flow may impact the wetlands. RTi conducted an initial study of the ground water system at the Waterfield Site during April, 1997. The results of this study were summarized in a report entitled Preliminary Evaluation of the Ground Water System at the Waterfield P.U.D. Site dated April, 1997. As part of this report, a potentiometric surface map vas constructed from existing ground water elevation information. The map indicates that the bask direction of ground water flow in the area of the First Filing; is to the south and not towards the wetlands area. If this is the case, diverting the collected ground water from the subdrain system to the detention area should not impact the wetlands. RTi is proposing to conduct additional ground water work at the Waterfield site during July and August, 1997. This work will consist of installing additional peizometers and modeling the ground water system using a model called "MODFLOW." The model will provide information on how the ground water system will be effected by the First Filing construction activities as well as future development that is planned for the site. If the model indicates that ground water flows from the First Filing area are supplementing the wetlands hydrology, the subdrain system will be redesigned and the collected ground water will be directed into the wetlands. Mr. Basil Harridan with the City of Fort Collins Storm Water Division is familiar with the applications of MODFLOW and will be contacted to review and comment on the results of the modeling program. grnrral&dwigl.dnc 0620,97 2290 E. Prospect Road, Suite 1 Fort Collins, Colorado 80525 (970) 484-7573 FAX: (970) 484-7593