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HomeMy WebLinkAbout~Master - Zoning Board of Adjustment Minutes 5-27-2009MINUTES OF THE REGULAR MEETING OF THE ZONING BOARD OF ADJUSTMENT AMES, IOWA MAY 27, 2009 The Ames Zoning Board of Adjustment (ZBA) met, pursuant to law, in regular session at 7:00 p.m. on May 27, 2009, in the Council Chambers of City Hall with the following members present: Bruce Calhoun, Elizabeth Erbes, Denise Link, Gary Taylor, and Thomas Weber. Staff members Sam Perry, Ray Anderson, Corey Mellies, Christina Murphy, John Dunn, and Judy Parks were also present. APPROVAL OF MINUTES: Moved by Erbes, seconded by Weber, to approve the minutes of the meeting of May 13, 2009. Vote on Motion: 5-0. Motion carried unanimously. CASE NO. 09-10 VARIANCE - CIVIL DESIGN ADVANTAGE, 205 SE 5TH STREET Continuance of Application for Variance from the Storm Water Management Design Standards for the property located at 205 Southeast 5th Street Chair Link stated that there were only four Board members present at the previous meeting, and the vote on this case was split (2-2). As no decision was reached, the hearing continued to this meeting. She also stated that Board Member Taylor, who was absent at the previous meeting, had reviewed the tape and so there was no need to revisit old evidence; however, they would hear any new evidence provided by Staff or the applicant. Assistant City Attorney Judy Parks stated that they have asked the Director of Water and Pollution Control John Dunn and the Assistant Director Christina Murphy to be present at this meeting to address some questions that the Board asked at the previous meeting, particularly about the well field to the east of the parcel. City Planner Sam Perry stated that the question from the last meeting was regarding the reasoning behind the restriction that City staff has placed on excavation below the existing grade. Director of the Water and Pollution Control Department John Dunn presented a map of the city’s four well fields, and gave details about their locations and times of drilling. He also showed a map of the “capture zone” of each well. Mr. Dunn explained that they are currently having a study conducted to delineate where each capture zone is, to help them understand what the sustainable drought yield of the aquifer is, and also to use the capture zone information to develop a well head protection ordinance for the community. He pointed out the southeast well field by the Skunk River and Squaw Creek in relation to the subject property. Mr. Dunn showed a map of the geological formation in Ames to illustrate what makes the subject property unique. He pointed out the wells in the ISU field, and explained what the different layers were on the map. He stated that there is a sand and gravel layer, and below that a layer of silt, which acts as a confining barrier to prevent surface materials from moving down into the formation. He said that below the layer of silt is the actual aquifer, which water is pulled from. Mr. Dunn indicated that in the downtown well field, there is an even larger layer of till that helps to confine and protect the aquifer in that formation. He stated that, in contrast, the southeast well field has no confining layer present, which makes it more susceptible to the movement of contaminants through the soil profile and into the capture zones of those wells. Mr. Dunn said that in that area, there is only eight to twelve feet of black topsoil on top of the sand and gravel, or water-bearing layer, which provides very limited cover over the formation in that area. He stressed that because of the lack of confining layer, the area around the subject property is very unique when compared to the areas around the other well fields. Assistant Director of Water and Pollution Control Christina Murphy showed a map and pointed out that there is roughly 1,000 feet between the center of the proposed development and the nearest well. Mr. Dunn also addressed Board Member Calhoun’s question from the previous meeting regarding the reasoning behind allowing a sanitary sewer system in the ground, but not allowing an open storage basin for water detention. He showed a map of the sanitary sewers that are in and around the well field. He went over a section of the Iowa Administrative Code relating to the design and construction of potable water supplies, which lays out the separation criteria necessary for separating supply wells from potential sources of contamination. Mr. Dunn relayed that the separation criteria for gravity sewers have two different standards, depending on the construction of the sewer. He stated that the separation criterion is approximately 50 feet if it is constructed to a water main specification, or 100 feet separation if constructed to a sewer pipe specification. Mr. Dunn referred to an issue with Super Wal-Mart regarding the possibility of its storm water detention basin being immediately close to the wells, and in that case the City staff contacted the Department of Natural Resources to find out what criteria they would apply to that storm water detention basin in the event that the well failed and would need to be re-drilled. The DNR replied that it would apply the wastewater lagoon separation criteria, which differ depending on whether they are being applied to a deep well or shallow well. Mr. Dunn explained that the well in question would be considered a shallow well, since there is no confining layer present to protect the well from surface contamination, and therefore the separation criteria would be 1,000 feet. Board Member Taylor asked if the well nearest Super Wal-Mart would need to be relocated if it failed. Ms. Murphy clarified that Super Wal-Mart’s storage is considered a bio-retention cell and would not fall under the previously stated criteria, which is exactly why it chose that system. Ms. Parks added that, originally, at the eastern edge of its site immediately next to the well, Super Wal-Mart had planned to do an open lagoon with a rubberized bottom to collect all of its storm water run-off. She stated that City staff, after considering the aforementioned criteria from the DNR, went back to the drawing board and decided that a bio-retention system, where water is captured underground and filtered before it is released and put back into the system, would be the best option. Mr. Dunn referred to the map that showed a square area around each well with the well centered directly in the middle. He explained that the City must maintain absolute control of the ground within a 200-foot radius around it, as required by the Department of Natural Resources. He stated that as long as they can keep contaminants out of the 400-foot square, the City can continue to use the well as a potable supply. Mr. Dunn said that the issue is, if the well ever fails, they would not be able to secure a permit to re-drill in the same location. Board Member Weber asked for clarification about the 1,000-foot separation, to which Mr. Dunn replied that the criteria require 1,000 feet of horizontal separation from the well head to the nearest source of contamination at the time the construction of the well is approved. He also explained that the permanent control of a 200-foot radius around the well is a standard that they must maintain throughout the life of the well. Ms. Parks asked Mr. Dunn to address another question from the previous meeting regarding quantity control versus quality control during small and large rain events. Mr. Dunn answered that the first flush coming off of the property carries the greatest amount of pollutants, and so a storm water quality treatment unit should be designed to take the first flush volume of water, and as the rain event continues, any additional rainfall is allowed to bypass the water quality treatment unit. Brad Kuehl, Civil Design Advantage, 5501 NW 112th Street, Grimes, Iowa, stated that it was very helpful to understand the overall process from Water and Pollution Control. Mr. Weber addressed Mr. Kuehl, and stated that he felt that there is a big problem with development, particularly with parking lots and run-off. He questioned how much fill they would put in on the parking lot. Mr. Kuehl replied that the fill would vary from two to six feet. Mr. Weber asked if they had investigated permeable parking surfaces to help alleviate run-off problems. Mr. Kuehl replied that they did look into it, and several factors including cost and needing rock underneath the porous pavement deterred them from that option. Mr. Weber stated that they have to put four feet of fill anyway, and went into possible options involving permeable parking. He reasoned that there are trade-offs for the higher cost of using porous pavement, such as longevity, and gave an example of a permeable lot that was poured over 20 years ago and is still in good shape, despite freezing and thawing conditions during winter. He emphasized that a large advantage of permeable parking is that the water seeps through the lot, rather than pooling. Mr. Kuehl stated that he appreciated the idea, but that they had determined that porous pavement did not make sense on their site. He added that porous pavement is not suitable for heavy truck traffic, which they would have on their site frequently. Board Member Calhoun stated that he felt that a permeable surface was an excellent idea, and challenged Mr. Kuehl about how they arrived at the conclusion that it would not work on their site. Mr. Weber said that he was very sympathetic to the problem of this site, but that he was still worried about upholding the ordinance to prevent excessive run-off during storms, which would impact people downstream, and was unsure whether they should make an exception to that rule. He said that he understands that the subject property is small and the effect would not be that significant, but he felt that if they make exceptions all the time, the result could be disastrous. He stated that he did not want to contribute to such a result. Board Member Taylor asked if they could meet the detention requirements with the two to six feet of fill that is currently proposed. Mr. Perry interjected that the applicants want to have a storm water design for the site as a whole, even though the request at hand is for just the Petco site. Mr. Taylor said that he understood that the storm water detention design takes into account the eventuality that the property will reach full build-out. Mr. Taylor asked if they could meet the 100-year detention standards by sacrificing some of the design, whether it be parking or future build-out. Mr. Kuehl said that indeed they could take away parking and/or development and meet the 100-year detention requirements, but that it would not be ideal. He stated that they arrived at the proposed site plan based on what makes sense economically for the site, and added that it was only as they were going through the review process that they learned about the restriction against excavation. Chair Link asked if they could sacrifice parking and not development and meet the standards. Mr. Kuehl stated that Petco requires more parking than the City’s minimum standards, and so the site plan for Petco has an additional 19 parking stalls. Ms. Link asked if they would still be above City requirements if all three buildings were built, and Mr. Kuehl replied that in the end they would still have just 19 extra stalls if everything was developed as planned. Steve Scott, Westown Associates LLC, 1701 48th Street, Suite 11, West Des Moines, Iowa, stated that they downsized their plan after they found the challenges that came along with the site, and explained that he did not want the Board to have the impression that they are trying to cram in as much development as possible. He said that they have reduced significantly from what would be ideal, but that they still need to achieve something economically feasible. Mr. Scott also discussed typical parking criteria for restaurants and retail use, and pointed out that very few restaurant concepts feel that the minimum number of spaces required is adequate. Mr. Perry spoke about the Board’s concern of downstream flooding, and pointed out that the subject property is at the bottom of the watershed. He also mentioned that the Board had asked what impact would be made if the subject property had no storm water quantity control whatsoever, and he stated that the answer is none. Mr. Perry recalled that several of the Board Members were apprehensive of allowing an exception for this property simply because the impact would be insignificant, reasoning that multiple small impacts could add up to a large problem. He asked Ms. Parks to address the question of when the Zoning Board’s role changes over to something that the City Council should be addressing. Ms. Parks stated that it is the Board’s role to look at this particular site. She explained that the City Council has made a legislative determination over a long period of time that floodplain development is allowed as long as standards are in place. She also mentioned that many properties along South Duff were flooded in 1993, but as they have come into redevelopment, they are significantly higher and they meet the standards. She stated that it was fine if the Board subjectively had a concern about what would happen downstream, but that issue really should be addressed by the City Council, because it relates to the whole development of the entire floodplain. Ms. Parks explained that the floodplain regulations assume that there is an equal amount of development that is allowed and will take place at each of those locations, and so the Board should look at what impact this particular one site would have in the grand scheme. Board Member Weber asked why there is an ordinance that specifies that run-off should not be any larger than at the pre-development stage. He reiterated the concern that every little piece adds up. Mr. Perry said that the Board should ask if the variance meets the criteria or not, and should base its decision on that. Mr. Weber stated that he was not trying to control the floodplain, but rather that he saw alternatives for the development that would meet all of the criteria. He restated his ideas about permeable parking in relation to the issue of run-off. Mr. Perry explained that City staff was not trying to sway the Board one way or the other, but that they wanted them to understand procedurally what its parameters were. Board Member Calhoun asked what the point was of saying that it didn’t matter if there was no storm water detention on the subject property. Public Works Civil Engineer Corey Mellies stated that he first wanted to address Mr. Weber’s question about water quality and filtration. He explained that City staff asked Civil Design Advantage to follow the Iowa Storm Water Management Manual, which provides a variety of sources for quality treatments, one of those being porous pavement, and another being the bio-retention system, which they chose. He stated that staff did not specify what method the applicant should use. Mr. Mellies addressed the site’s run-off being insignificant, and stated that the impact of the volume of water at this site in the grand scheme of the Skunk River Basin would be almost a zero percentage. Mr. Calhoun asked why that was important, and it was determined that City staff had been addressing a question from the previous meeting. Board Members Weber and Calhoun conversed about the idea of permeable parking. Mr. Mellies discussed the idea with them, and explained some of the standards behind that kind of design. Moved by Erbes, seconded by Link, that the Zoning Board of Adjustment adopt CASE NO. 09-10 granting a variance from the minimum Storm Water Design Standards at the property located at 205 Southeast 5th Street. Roll call vote: 2-3. Voting Aye: Link, Erbes. Voting Nay: Taylor, Weber, Calhoun. Motion failed. COMMENTS: There were no comments by the Board. ADJOURNMENT: The meeting adjourned at 8:04 p.m. __________________________________ ___________________________________ Emily Burton, Recording Secretary Denise Link, Chair