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6.a)2)c. Open Space Conservation Subdivisions and Coummunity Water Systems • �� f �/� �� l,s ♦ i _ � �� � � tu` �\ � ,..�- �. � . . �. � ' �,,,,,,,._� �!"...� r ,ti' i �B \. �` .. .:s` ��..l°'<' l�.. � c ' � •` - .���.Nl�I�. �� Memo - � � To: Mayor and Council Planning Commission From: Anne Hurlburt,City Administrator Date: May 27,2010 for Discussion at June 1,2010 Meeting Re: Open Space Conservation Subdivisions (OSCS) and Community Water Systems Currently the Development Code encourages community sewer and water systems in OSCS,and awards bonus density for such systems. The Preliminary Plat for the Tii Gavo project included a community well. After further consideration, the developer asked to eliminate the water system in favor of individual wells,which the City Council approved as an amendment to the Preliminary Plat. Attached is a copy of a staff report provided to the Council when that decision was made in May of 2007. It summarizes the advantage and disadvantages of a community well. You may wish to consider this information when determining whether the revised OSCS standards should encourage or provide a density bonus for a community well. 1 Meeting Date: 5/1/2007 Agenda Item: Planning Commission/City Council Agenda Report City of Scandia 14727 209th St. North, P.O. Box 128 Scandia, MN 55073 (651) 433-2274 Action Requested: Hold a public hearing and consider the application of Big Marine Development, LLC. to amend the Preliminary Plat for the Tii Gavo Open Space Conservation Subdivision. Deadline/ Timeline: Application was received on Apri] 12, 2007. 120-day review period ends July 11, 2007. The Final Plat application is incomplete. Background: • At the April 3, 2007 meeting, the Planning Commission and Council found that the elimination of the community well from the project was a material change to the Preliminary plat, requiring an amendment (including a public hearing) before Final Plat approval. • The project is an open space subdivision and a planned unit development (PUD). The yield plan showed a maximum of 28 lots without density bonuses, 19 in the first tier of the Shoreland District and 9 lots in the underlying Agriculture District. The project was awarded the maximum density bonus of 100%of the number of lots outside the Shoreland (91ots) for a total of 371ots in the project. The project was also given PUD flexibility to permit lot sizes smaller than 1.5 acres and buildable area less than 1 acre, and for several other features of the project (such as the community building and accessory storage buildings.) • The ordinance requirements for open space/ conservation subdivisions have changed since preliminary plat approval of this project. State law does not allow the city to apply the new ordinance to this project, as the preliminary plat approval was less than one year ago. However, a rough analysis of the project, prepared by TKDA during discussion of the new ordinance, indicated that Tii Gavo may have received a density bonus of 95% under the new ordinance; 80%without the community well (see the table, attached.) Under the former ordinance, the density Page 1 of 3 OS/27/10 bonus was a more subjective matter subject to negotiation, without specific percentages for particular features. Therefore it is not clear how much, if any, of the bonus awarded was attributable solely to the community well. This needs to be determined by the Planning Commission and City Council. • The applicant has submitted a narrative explaining their arguments in favor of individual wells vs. a community well. Staff has also consulted with an engineer knowledgeable in the area of water supply(Bernie Bullert, TKDA) for advice. The consensus seems to be that the disadvantages may outweigh the advantages of a community well. • Advantages of a community well appear to include: ➢ The conventional wisdom seems to be that fewer holes in the ground eyuals less risk of contamination of the groundwater supply. This has been advocated by the DNR. ➢ In the event of contamination of the water supply, it may be easier to provide needed treatment at a single well, rather than individual wells. ➢ A community well may be more closely monitored than individua] wells, so a problem with contamination might be discovered more quickly. ➢ If it was ever necessary to provide a public water supply to the area, the water mains would already be in place. • Disadvantages of a community well appear to include: ➢ The cost of the water system will be greater, particular where the lots are large and significant lengths of pipe are required to construct the distribution system. ➢ The environmental impacts from grading, vegetation removal and materials used for construction of the water distribution system could be significant. ➢ A single, high-capacity well could have a larger impact on deeper underground water levels ("cone of depression") than many lower-capacity wells (but not as widespread as multiple individual wells.) ➢ While the DNR advocates fewer wells, the Minnesota Department of Health does not, indicating that if wells are constructed to meet well codes the additional risk of contamination is not significant. No significant risk of contamination has been identified at this site. ➢ Chemical treatment (such as with chlorine, or iron removal) could be required because of the size of the system, adding significantly to the cost. ➢ While treatment at a single well might have some advantages, some types of treatment (such as softening) would probably still only be economically feasible at each home. ➢ Long-term management of the water system might be more Page 2 of 3 OS/27/10 than a homeowner's association could handle, financially and practically, especially if it was necessary to hire a licensed firm or individual to operate the system. ➢ Even though water mains would be in place, it is likely that the system would not be built to the same standards that would be required for a municipal system. This would reduce some of the potential advantage should a public water supply be necessary in the future. • The city's new ordinance for Open Space Conservation Subdivisions does give a substantial bonus for community wells (15%). This exceeds the bonus for many other features; the bonus for community sewage disposal systems, for example, is 10%. The city may wish to reconsider that part of the ordinance in the future. Recommendation: After holding the public hearing you should determine whether or not the proposed amendment deleting the community well should be approved, and whether or not this would require other changes to the plat, such as a different density bonus. A draft resolution allowing elimination of the community well has been provided for consideration. It can be modified as necessary if additional changes to the preliminary plat would be required. Attachments/ • Application for Preliminary Plat Amendment Materials provided: . Letter dated April 17, 2007 from CMWD Engineer Daniel Fabian, EOR • TKDA Memorandum Dated July 6, 29006 (Analysis of Preliminary Plat) • TKDA Memorandum Dated July 28, 2006 • Excerpt of Town Board Minutes, September 5, 2006 • Tii Gavo- Test far Draft Conservation Subdivision amendment • Draft Resolution OS-O]-07-03 Contact(s): Prepared by: Anne Hurlburt, Administrator (tii gavo prelim plat amendment) Page 3 of 3 OS/27/10