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Home My WebLink About15.B.1. Consider Extension Agreement for the Dean Lake Outlet Control Structure Design, Project No. 2004-4 J~ G . / . CITY OF SHAKOPEE CONSENT Memorandum TO: Mayor & City Council Mark McNeill, City Administrator FROM: Bruce Loney, Public Works Director SUBJECT: Consider Extension Agreement for the Dean Lake Outlet Control Structure Design, Project No. 2004-4 DATE: May 3, 2005 INTRODUCTION: Attached is an extension agreement with WSB & Associates, Inc. to provide engineering services for the final design of the Dean Lake Outlet Control Structure for Council consideration. BACKGROUND: The Dean Lake Control Structure Project has been discussed and initiated since November 6, 1996 with the Dean Lake Control Structure feasibility report and authorization for preliminary design in September, 1999. The City of Shakopee did a preliminary design and did receive a Department of Natural Resources (DNR) permit and Army Corp permit to construct a control structure. Due to several issues on the lake as to the operation of the control structure, cost sharing with the Prior Lake-Spring Lake Watershed District and the desire to have further studies before the final design, the proj ect was delayed. Additional studies along Dean Lake was to determine the lake elevations at various points along the lake, to perform water quality studies on Dean Lake and to have meetings with the Army Corps of Engineers (ACOE), DNR, Lower Minnesota River Watershed District (LMRWD) and Prior Lake-Spring Lake Watershed District (PLSLWD), as well as residents on Dean Lake before proceeding to a final design. In 2004 staff did an inspection of the channel outlet from Dean Lake to T.R. 169 box culvert and noticed considerable erosion of the channel since 1999. Staff began in earnest to proceed with further meetings and discussions with groups in order to proceed with final design on the outlet control structure. Initially, the DNR permit did permit the runoff control elevation, which was measured in 1999 to be set at 745.7. The normal lake elevation is approximately 746 with the ordinary high water (ORW) elevation at 747 and the 100-year flood elevation at 749. In meetings with the residents and other interested parties, including the City's Environmental Advisory Committee, the desire was to maintain as much water in the lake as possible. Further review of the runoff elevations, and in meeting with the DNR, a runoff elevation could be set in between 745.7 and 746.9. In a previous study done by the City's consultant, WSB & Associates, Inc., had indicated that a 746.5 runoff elevation would seem to be the best elevation in maintaining the highest water level in Dean Lake and yet maintain the 100-year flood elevation of 749, previously established in studies on Dean Lake. Staff has attended a LMRWD meeting on proceeding on final design and will meet with the LMRWD on our final design.and final runoff elevation. Preliminary indications is that the LMRWD does support the City in its runoff elevation determination of 746.5. However, this will be verified in future meetings with the LMRWD. Staff has also met with the Environmental Advisory Committee and did receive a recommendation to proceed with final design of the Dean Lake Control Structure in order to prevent further erosion of the existing channel and environmental damage which is occurring. This project ispart ofthe Prior Lake Outlet Channel and would qualify for cost sharing of those entities involved in the Joint Powers Agreement of the channel. Recent meetings between the Cities of Prior Lake and Shakopee, PLSL WD and Shakopee Mdewakanton Sioux Community have been productive and a new agreement for cost sharing is expected in a couple of months. It is hoped that the agreement would be ready for Council action prior to construction of the Dean Lake Control Structure. Attached to this memo, for Council review, are letters that have been sent to the LMRWD with attachments and letters from the DNR with attachments in regard to this issue. Another issue that residents have raised, in association with the lake, is the OHW level of 747. Staffs determination, in this matter, is that this is a separate issue from the runoff elevation and control structure which needs to be constructed for Dean Lake. The OHW elevation is a jurisdictional elevation that is determined by the DNR and they have made a determination that 747 is the OHW level and the DNR sees no reason to change the elevation at this time. The matter for Council, at this time, is to consider authorizing WSB & Associates, Inc. to proceed with the final design, as per the attached extension agreement for the Dean Lake Outlet Control Structure final design. The final design will determine 'the location of the structure and amount of channel restoration while considering future trail and pedestrian bridge over T .H. 169. ALTERNATIVES: 1. Authorize the appropriate City officials to execute an extension agreement with WSB & Associates, Inc. for engineering services for the Dean Lake Outlet Control Structure final design, Project No. 2004-4. 2. Do not authorize an extension agreement with WSB & Associates, Inc., at this time. 3. Table for additional information. RECOMMENDATION: Staff would recommend Alternative No.1, in order to proceed with final design and for possible construction yet this year for the Dean Lake Control Structure. ACTION REQUESTED: Authorize the appropriate City officials to execute an extension agreement with WSB & Associates, Inc. for engineering services for the Dean Lake Outlet Control Structure final design, Project No. 2004-4. ~~ Bruce Loney Public Works Director BUpmp ENGR/2004PROJECT/DEANLAKE/WORDIFINALDESIGN ~ WSB & Associates, Inc, Infrastructure I Engineering I Planning I Construction 701 Xenia Avenue South Suite 300 Minneapolis, MN 55416 February 22, 2005 Tel: 763-541-4800 Fax: 763-541.1700 Mr. Bruce Loney, P.R Public Works Director/City Engineer City of Shakopee 129 Holmes Street South Shakopee, MN 55379-1376 Re: Extension Agreement to Provide Engineering Services for the Dean Lake Outlet Final Design WSB Project No. 1281-74 Dear Mr. Loney: WSB & Associates, Inc. proposes to complete the following Scope of Services as it relates to preparing the final construction plans, permit applications, and construction documents for the Dean Lake Outlet Structure. The Scope of Services proposed is provided below: I. Project Management This task anticipates attending up to six (6) meetings with the City, residents, Lower Minnesota River Watershed District, Prior Lake/Spring Lake Watershed District, City of Shakopee Environmental Advisory Committee, and the City Council. The purpose of these meetings will be to discuss the design parameters of the proposed outlet, and also to discuss changes in the operational plans for the Dean Lake bypass structure, as directed by the governing watershed districts. It is our goal that the project manager will keep the City apprised of changes in permit requirements and issues as they relate to the Dean Lake outlet improvement. II. Permit Application The Dean Lake outlet structure currently has received permit approvals from the Army Corps of Engineers and the Minnesota Department of Natural Resources. These permits will be revised and submitted to the approving agencies; they will include the new elevations and proposed design of the outlet structure. WSB will follow-up with the agencies to secure the permits for construction of the Dean Lake outlet structure. III. Preparation of Construction Plans and Specifications This task includes preparation of construction plans and specifications for the construction ofthe Dean Lake outlet iInprovement. WSB & Associates, Inc. will prepare the necessary contract Minneapolis I St. Cloud Equal Opportunity Employer F: IWP WINI / J81-7 4\LTR-exlellserv-OI31 oS.c/oc Mr. Bruce Loney Page 2 documents for the bid process and assist the City staff in receiving the bids and providing a recommendation to Council for award of the contract. IV. Construction Management WSB & Associates, Inc. will provide survey, observation, and construction management as necessary for construction of the Dean Lake outlet structure. WSB & Associates, Inc. proposes to provide the above Scope of Services for a cost of $9,500 to $11,500 with a cost not to exceed $12,500. The proposed project schedule is attached. This schedule may vary due to the decision-making process and approvals by the various review agencies. Sincerely, WSB & Associates, Inc. ./-V' 47---, Todd E. Hubmer, P.E. Associate City Administrator lh/tsh City Clerk Mayor Date F: IWPWIMJ l81-74IL TR-ex/el/serv-Ol] J OS.doc PROPOSED DEAN LAKE OUTLET SCHEDULE 1. Meet with Review Agencies ....................................................;.............................. March 2005 2. Prepare Preliminary Outlet Plan and Operational Plan/Submit to Review Agencies. .............. ....... ............ ....... ................. .... ....... .......... April 2005 3. Receive Comments from Review Agencies ................;.............................................. May 2005 4. Make Revisions and Submit Final Plans and Permits forReview Agency Approval................................................................. May 2005 5. Receive Permits and Approvals ................................................................................... July 2005 6. Prepare Construction Documents and Advertise Project forBid .. .... ..... .......... ....................... ..................... ..... .... .............. August 2005 7. Construct Outlet Structure ................................................................... October-December 2005 F:\WPWlNl1281-74Iproposed schedule. doc 5. -.. ~"""~::.:r.-'~l'e"tWlU ~ .........'""~ 701 Xenia Avenue South, Suite 300 Minneapolis, MN 55416 WSB www.wsbeng.com ~ & Associates, Inc. April 8, 2005 "_ 763-541-4800. Fax 763-541-1700 INFRASTRUCTURE I ENGINEERING I PLANNING I CONSTRUCTION Environmental Advisory Committee c/o Bruce Loney City of Shakopee 129 Holmes Street South Shakopee,~ 55379-1328 Re: Final Design of Dean Lake Outlet City of Shakopee, MN WSB Project No. 1281-83 Dear Mr. Loney and EAC Commissioners: This letter is intended to provide you with an update on the Dean Lake Outlet and to request your con~ideration on providing a recommendation to the City Council for proceeding to fmal design. The City and WSB presented the current Dean Lake outlet proposal to the Lower Minnesota River Watershed District (LMRWD) at their last monthly meeting. We discussed the proposed design and any concerns which they may have in regard to this design. Attached is a copy of our correspondence to the LMR WD board. Based on conversations with the LMR WD board and others the following issues will be addressed during fmal design: 1. Operational plan for the Dean Lake by-pass channel 2. Stabilization of the Dean Lake Outlet Channel downstream. of the proposed outlet location 3. Maintain the 100-HWL elevation in Dean Lake at 749.0 4. Outlet should attempt to mimic historical outlet performance 5. Verify that septic systems will not be adversely impacted by the proposed outlet 6. Evaluate opportunities to improve the quality of water entering Dean Lake from the Prior Lake outlet channel. Furfuennore, the City, LMRWD and the MDNR have received comments related to the OHW for Dean Lake. In regard to this discussion, please review the MDNR comments contained in the attachment. We request that the discussion associated with the OHW for Dean Lake not be confused with the establishment of the run-out elevation from the Lake. The run-out elevation of the Dean Lake outlet must occur between elevations 745.7 and 746.9 as determined by the C:\Documenls and Setttngs1mlhemigILocal SetttngslTemporary [nlemel Filesl0LK9BIEIl1'ironmenlal Advisory Commltlee.doc . GfyL 'A WSB . I ;Lfj; ~f3 Rmo~"""'~~ Infrastructure I Engineering I Planning I Construction 701 Xenia Avenue South & Associates. Inc. Suite 300 March 8, 2005 Minneapolis, MN 55416 Tel: 763-541-4800 "- Fax: 763-541-1700 ' - Mr. Terry Schwalbe, Administrator Lower Minnesota River Watershed District 200 4th Avenue West Shakopee~ MN 55379 Re: Proposed Outlet Improvements for Deans Lake . City of Shakopee, MN . WSB Project No. 1281-83 Dear Mr. Schwalbe: i This letter is wntten in response to yoUr request for information about the pelTIlanent outlet structure being proposed for Deans Lake in the City of Shakopee. The key remai~g issues, as they relate to the outlet from Deans Lake, appear to be the following: 1. The nonnal run out elevation from the outlet structure at Deans Lake. 2. The proposed operational plan for the Deans Lake bypass. 3. As established by the Minnesota Department of Natural Resources, ordinary high water level of747 :0. The City would like to provide the following information as it relates to these concerns: 1. The City of Shakopee currently has in place permits to construct a pelTIlanent outlet from Deans Lake at elevation 745.7 from United States Corps of Army Engineers and the Minnesota Department of Natural Resources. 2. The City of Shakopee in response to residential concerns has proposed to revise the nm out elevation from elevation 745.7to elevation 746.5. 3. The proposed outlet from Deans Lake will be designed to operate with a fluctuation between elevation 746.5 and 747.0 during the operation ofthe Prior Lake/Spring Lake outlet channel. 4. The currently proposed outlet structure from Deans Lake has a pennanent nm out elevation Qf746.5 and an anticipated lOa-year high water elevation of749.0. There has been much thought put into Deans Lake as it relates to the anticipated run out elevation and the lOa-year high water elevation. The issue(s surrounding these elevations are as follows: a. All housing and development adjacent to Deans Lake have .been built over the years with an anticipated lOa-year high water elevation of749.0. The City of, Minneapolis I St. Cloud K:IOJ131-33lM",iI/IDocsILTR - Ire/lll"II1. - 030705."oc Equal Opportunity Employer . L)-tL 'A WSB I ;;L1J/~f3 ..........._s""~ Infrastructure I Engineering I Planning I Construction 701 Xenia Avenue South & Associates, lnc, Suite 300 March 8, 2005 Minneapolis, MN 55416 Tel: 763-54H800 - Fax: 763-541-1700 . Mr. Terry Schwalbe, Administrator Lower Minnesota River Watershed District 200 4th Avenue West Shakopee, MN 55379 Re: Proposed Outlet Improvements for Deans Lake , City of Shakopee, MN , WSB Project No. 1281,,83 Dear Mr. Schwalbe: ;' This letter is written in response to your request for information about the permanent outlet structure being proposed for Deans Lake in the City of Shakopee. The key remaining issues, as they relate to the outlet from Deans Lake, appear to be the following: ' 1. The normal nm out elevation from the outlet structure at Deans Lake. 2. The proposed operational plan for the Deans Lake bypass. 3. As established by the Minnesota Department of Natural Resources, ordinary high water level of747:0. The City would like to provide the following information as it relates to these concerns: 1. The City of Shakopee currently has in place permits to construct a permanent outlet from Deans Lake at elevation 745.7 from United States Corps of Army Engineers and the Minnesota Department of Natural Resources. 2. The City of Shakopee in response to residential concerns has proposed to revise the nm out elevation from elevation 745.7 to elevation 746.5. 3. The proposed outlet from Deans Lake will be designed to operate with a fluctuation between elevation 746.5 and 747.0 during the operation of the Prior Lake/Spring Lake outlet channel. 4. The currently proposed outlet structure from Deans Lake has a permanent run out elevation qf746.5 and an anticipated 100-yearhigh water elevation of749.0. There has been much thought put into Deans Lake as it relates to the anticipated nm out elevation and the 1 OO-year high water elevation. The issu~s surrounding these elevations are as follows: a. All housing and development adjacent to Deans Lake have ,been built over the years with an anticipated 100-year high water elevation of749.0. The City of. Minneapolis I St. Cloud K:l0/28/-83lMminlDocslL TR - /so/"",/I,. - 03070.l.doc Equal Opportunity Employer . Mr. Terry Schwalb~ .... March 8, 2005 Page 2 Shakopee requires that the adjacent structures maintain 3-feet of freeboard between the building opening and the anticipated 100- year high water level of Deans Lake. Increasing the I DO-year high water elevation of Deans Lake could increase the flood risks to properties adj acent to the lake. b. Should water elevations exceed 749.0, there is no available emergency overflow to handle stOffi1S in excess of the 100-year event. TH169 does not overtop until approximate elevation 752.0. Therefore, reducing the allowable freeboard between the 1 DO-year high water elevation and the adjacent homes could result in significant damage ror extreme storm events, such as the event ofJuly 11,2000 when ll-inches ofrain fell in Eagan. c. The current nm out elevation from Deans Lake has been chosen such that it will not adversely affect vegetation adjacent to Deans Lake. An elevation above 746.5 may impact existing vegetation and habitats surrounding Deans Lake. . 5. The City of Shakopee proposes to split the flow of the Prior Lake/Spring Lake outlet channel, thereby allowing the base flow discharges from the Prior Lake/Spring Lake outlet channel to be discharged both into DeansLake and also tbroughthe bypass structure. Tlus will supply adequate water to meet the hydrologic needs of both wetland complexes. The propm?ed discharge rates to both Deans Lake and the bypass will be provided on submittal of final design documents for your review. 6. Attached for your information is correspondence from the Minnesota Department of Natural Resources as it relates to the discussion of the ordinary high water level at Deans Lake. The City has not expressed any desire to request additional reviews of the ordinary high water level for Deans Lake.. We would like the opportunity to discuss these issues and any other issues the Lower Minnesota River W. at,ershed District may have as it relates to the preparation of fmalplans for the construction of a permanent outlet structure from 'beans La~e. We will be present at your March 16, 2005 meeting. to review these issues with the board. If you have any questions, please feel free to contact me at 763-287-7182. Sincerely, , WSB & Associates, Inc. ?~/ Todd E. Hubmer, P.E. Proj ect Manager Attachment cc: Bruce Loney, City of Shakopee tsh K:\OI :81.83IAclllliI/IDocsILTR . tsc/llmfh. - 030705.cloc -.> Minnesota Department of ~atural Resources D~1r-,~)~', . . , Central Region Waters - 1200 Warner Road~St. Paul, MN 55106-6793' Telephone: (651) 772-7910 Fax: (651) 772-7977 FES 1 0 2nn:~ \j\J~t'1 n P,t'~("'." .:0:,"',...... , . ~D Cl ., !;;"~\. .,... . '~~. :rd' q. February 8, 2005 Bruce Loney City of Shakope~ 129 So. Holmes Street Shakopee, Minnesota 55379 RE: . Dean's Lake (#70-74P) , , pearlvfr. Loney: As you requested, I cut and pasted several past e-mails regarding Dean's Lake, its long standing Ordinary High Water Level (OHW) , and permissible runout level. To date, there are only a few individual property owners on the south side of the basin that continue to question the OHW that was established, then revisited twice, by DNR. None of the units of government irivolved in this matter over the years have expressed reservation about the OHW that was established, or the methodology used to arrive at the elevation. I anticipate that I and one of our surveyors will continue to shoot the water surface elf~vation and reset the lake gage every spring.' We now also have a regular gage reader on the lake' that submits .lake level readings for inclusion in our statewide database. From: Pat Lynch rmailto:oat.lvnch@)dnr:state.mn.usl Sent: Monday, October 18, 20041:15 PM To: Bob Potocnik Cc: BLonev@)ci.shakooee.mn.us; Glen Yakel; John Scherek; Mel Sinn Subject: Dean Lake Benchmarks,. Basin #70-74P I met last week (qctober 11) with a survey crew from WSB & Assodates to . have them shoot elevations at a number of locations around Dean's Lake in Shako pee. WSB was working on behalf of the City of Shakopee. . The WSB surveyors had GPS-based equipment. Relevant findings were .as follows, and in 1929 datum: LakesDB describes a DNR benchmark as 8evation: 761.69 ft, Date Set: 02/27/1980 . Datum: 1929 Benchmark Location Township: 115 Range: 22 Section: 15 Description: A 60d spike in the north side of trans. pole on south side of road in Haworth yard. I found this 8M last week. The Haworth's stiJllive there. WSB obtained an elevation of 761.69', exactly as we set it! . We have an obwell (#4J on the Czaja property on the southwest side of the lake. This was located and shot at 755.02' last week. We have it at 755.04' in our records. ~ I had them shoot a WSEfor Dean Lake near our lake gage. They shot 746.25'. I read 746.15', based upon our temporary staff gage. DNR Inform~tion: 65 j -296-6157 . 1-888-646-6367 . TTY: 651-296-5484 . 1-800-657-3929 All EqLWI Upptll"lunily EllIplllycr ~ PrinlcLllln R.ccydcLl P"pcr CIIIH.linilll! " ~ MinilllUll1 (\1" ~O',i PllSI-CI1I1SUIllCr W~I';IC -. 'f ,:,: - The north rim of the sanitary sewer manhole cover near our lake gage was shot at 755.75'. I believe we have it at 755.6', , I was quite satisfied with the findings. At least when the city and . DNR are discussing elevations, we know we are comparing apples to apples. Severcillocals swear the water level iO the wetland is lower, in general, than it has been in past years. The WSE last week is 0.38 of a foot below, the average water level based upon recorded levels reported in LakesDB. This is no surprise, since a significant contribution to the Deans Lake hydrology is from the Prior Lake outlet, . which hadn't been outletting since July 19 of this year. We (the city and me) are still looking at the outlet on the north side of the lake to see if our suspicions about the outlet being lowered by erosion and scour are true. The sandy soils and high discharge when Prior Lake is outletting through Deans Lake provide conditions conducive to downcutting of the <;hannel. Thanks a lot for all your help with this. I really appreciate it I Please place a copy of this e-mail in the Dean Lake file at Central Office. .' ... .---Original Message----. From: Pat Lynch rmailto:oat.lvnch((l)dnr.state.mn.usl Sent: Tuesday, August 03, 2004 6:27 AM To: blonev@)cLshakooee.mn.us Subject: Fwd: Re: Dean Lake (70-74P), Scott County I forwarded all the relative e-rnails that I have seen the last 5 weeks to th~ supervisor of the group wl)o performs the OHW investigations for the state.. Below is the response I got to the inquiry about the Dean Lake OHW. It appears to support my June 30 e-mail to you and Mr. Leek. >>> Glen Yakel 8/2/04 4:39 PM >>> Pat. . I have reviewed our field survey information for Dean Lake. The OHW was determined by the Hydrographics survey crew in September, 1977 to be , at elevation 747.0, and is based on the best available vegetation growing around the perimeter of the lake. Recorded spring lake levels range as much as a foot above the OHW, which is not an uncommon occurrence for a M"innesota lake. Also, the most recently determined runput elevation for Dean Lake is at 745.7, or 1.3' below the OHW, which compares favorably to the OHW. The few lake level readings on file show a I.ake fluctuating both , above and below the OHW - typical for a Minnesota lake. Nothing in the record indicates. that the OHW for Dean Lake, which. has been used by the City of Shako pee since 1977, is incorrect, Glen Yakel Hydrographics Supervisor DNR Waters (651) 296-4805 olen. va kel(Ci)dnr .state. mn. us - From: Pat Lynch rmailto:oat.lvnch@)dnr.state.mn.usl Sent: Wednesday, June 30, 2004 12:02 PM To: blonev(Ci)ci.shakooee.mn.us; MLeek(lilci.shakooee.mn.us Subject: RE: Dean Lake development gentlemen: Thank you for including me in your correspondence. Seems once every year or so I have to go over the history of Dean Lake, as our files , - would have it. It is a shallow water table wetland that historically was provid.ed its hydrology from the water table (surfidal) aquifer. This was verified by DNR studies in the early 1980's and mid-1990's, - when some thought the Shiely quarry dewatering would dry the lake up; . it never did. Pumping from the buried bedrock aquifer has little to no effect on Dean.Lake. Information from 1978, when DNR identified the wetland as being of the size and type tobe regulated by DNR, notes on the Field data sheet indicate Dean lake ,!S . a marginal type 4 wetland, subject todryin9 out.. It further indicates the basin had an average' . depth of 3.5 .feet and a maximum depth of 5 feet. It indicates that annual water level fluctuations of 2-3 feet were normal. The 1954 USGS quad map has a .water elevation of 746. the 1901 quad, while not showing a lake elevation, shows a small open-water area surrounded by considerable emergent wetland fringe. DNR established the OHW of Dean Lake based upon long Standing procedures. Based upon the physical water level indicators (hard and , softwood trees, ice ridges, stains on trees and boulders, etc.) visible. , around the wetland, an OHW of 747.0' was determined. This is not a normal water level; average water level, .or high. water level.. It Is not based upon any statistical analysis of water level readings. It is purely based upon the physical evidence left on the landscape. It does not deFIne the edge of wetland. 90% of the time, a delineated wetland edge will be higher in elevation than the OHW. This is certainly the case at Dean Lake. I looked at the water level data we do. have for the lake. It is available to anyone on our web site. we have data, off and on, back to the late 1970~s, with some gaps in the 90's. for all the readings, the average water level is 746.52'. This spring (April 19, 2004) when I surveyed it, the level was 746.17'. These eleva~ons are very much in line with an OHW of 747'. I also looked at air photo on the Scott County website. Photos from 2000 and 2003 have a large percentage of the wetland in open water. If you look at quads and photos before the Prior Lake outlet was opened and before the wet 1980's and 1990's, the amount of open water was considerably less. Truth is, the wetland would be of higher ~ological value if it were 2-3 feet deep. That would be more benefidal for waterfowl and furbearers, less condudve to rough fish survival, and would likely result in greater vegetative diversity. The Prior Lake outlet provides a lot of the hydrology to the lake now. Coupled with an lneffident outlet (it meanders through the floodplain forest and type 2 wetland), the additional hydrology from Prior Lake and fluctuations in water table elevation, it comes as no surprise that the surface water elevation of Dean Lake fluctuates. Nothing about the water levels I have observed have been alarming or'surprising to me. I am comfortable with the OHW of 747.0', and see no reason to revisit it. The outlet structure, yet to be constructed, has been discussed extensively. It was permitted, following the required review process by the DNR, watershed district, SWCO, etc.. I have no time to go back and revisit that matter unless the city sees some compelling reason to do so. As far as trespass, I can't address that. As Michael indicates, It depends on who owns the bed, whether or not it Is navigable, whether it is posted, or permission granted, what activity one is engaged in. ~ Regarding the cattail and algae concerns, I suggest that folks from the DNR aquatic plant management program be contacted with any questions or concerns. They work out the DNR Fisheries office here at 651-772-7950. Hope this helps, at least a bit. Feel free to pass this info along to anyone who may be interested. Pat Lynch r " - ---Original Message--- From: Pat Lynch rmailto:oat.lvnch@)dnr.state.mn.usl Sent: Thursday, September 09, 2004 7:58 AM To: aweber(lj)ci.shakooee.mn.us; BLbnev@)ci.shakooee.mn.us; JSwentek(iilci .shakooee.mn.us; JWevandt(a)ci .shakooee. mn .us; MLeek@)ci.shakooee.mn.us; MMcneil1 (1i)ci.shakooee. mn.us; MThemia(a)ci .shakooee. mn.us; tmeiller(lj)ci .shakooee. mn.us; pshutroo@)co.scott.mn.us; k oerl@)hotmail.com;' terrvs(a)lowermn.com; slotthammer@)olslwd.ora; ematthiesen@)wentk.com; smenden(iilwenck.com; AMoffatt(cilwsbena.comj Thubmer@)wsbeno.com; thubner@)wsaena.com Subject: Re: Dean Lake Outlet Mtg Bruce , et al: , Thanks for hosting last week's meeting. I hope all came away with it , better understanding of the regulatory, environmental, hydrologic and engineering issues associated with water level management at-Dean's - ..... ... '.' Lake. A couple things in Ms. Gerlach's recent e-mail need to be clarified right away; items #1 and #3 and #4, in particular. - 1. The outlet elevations. Further surveying to take place. Consideration of adjustments to higher levels (747 or 748) to ensure maximum retention of water that is conveyed into Dean lake, by whatever means. . . All agreed additional survey work, particularly a profile of the outlet channel and identification of the current runout control elevation.. A normal water level. (runout elevation) above 747' is not allowable under the laws and rules we are bound by. There is nothing in the record that suggests the basin maintained a normal water level above..747 historically. What the rules say are this: WATER LEVEL CONTROLS. - Subpart 1. Goals. It is the goal of the department to manage public waters to: - ...-r .... A. maintain or restore natural flow and natural water level conditions to the maximum feasible extent; B. encourage the construction of small off-channel retarding structures for the con.servation of water in altered, natural waterbasins, consistent with any overall plans for the affected watershed area; and C. limit the artificial manipulation of water levels, except when the balance of affected public interests dearly. warrants the establishment of appropriate controls and it is not proposed solely to satisfy private. interests. They. also say: Subp. 3. Prohibited water level control facilities. Construction or reconstruction of water level control facilities is prohibited when it is intended to manipulate water levels solely to satisfy private interests. Further, they say, F. the construction or reconstruction of water level control structures or changing the level of an existing structure shall be approved only to: (1) control and store flood waters; (2) maintain low flows for instream flow or water 'r level protection; (3) manage water quality, including the prevention or control of;erosion and sedimentationi . (4) improve water-based ret:r"eation; (5) create, improve, and maintain water supplies; (6) create, improve, or maintain aquatic habitat for fish and wildlife spedesi . (7) establish, improve, or maintain the generation of hydroelectric power; or . (8) restore the existing control elevation to a historic natural water elevation if detailed engineering surveys establish that the proposed control elevation does not exceed , the estimated naturCjI control. elevation; , In particular, read the goals.l.tbe .fi.rst part of the n,lles I included . - : ". .'. . .. ." R" .... ." . . ..,," . ..... above). 3. Acknowledgment and consideration of the petition by lakeshore owners to set the ordinary high water level at 748' accepted and recorded by the City "1984. Study and consideration of recent challenges to the set OHWL of 747' made by west end lakeshore owners. - I don't understand where the disconnect is between me and some on the - OHWL. It is not set by petition. It is based upon the physical water , level indicators on the landscape. In the case of Deans'Lake, it was determined to be at 747. That elevation was reaffirmed when our surveyors revisited the lake in 1983. As our web!jite states, "The Ordinary High Water Level (OHWL) is a term that many lake, wetland, and river property owners hear, but it is often misunderstood." What the OHWL is 'NOT: . a runout elevation - an average water level , . an extreme high water level - an arbitrary elevation set by an individual, group, or. agency 'The OHWL has no significance with respect to private ownership of the underlying bed. My suggestion to the dty is to not spend a lot of time on this one, instead, focusing on the appropriate control elevation. The runout elevation that is currently permitted, or which may be modified under permit, has absolutely no bearing on the OHWL, nor does the OHWL have any bearing on the f"!Jnout elevation. 4. Development of vision and purpose for Dean Lake in light of the many changes engineered in the last 20 years "and the new plans for significant residential communities, trails, and parks adjacent to this 250 acre lake. Reasearch into aquatic weed control, further dredging and water quality. If the thought here is removal of sediment near the mouth. of the Prior Lake channel where it enters Deans Lake, I am ok with that. There is very little likelihood that sediment is carried very far in to the lake-proper. The velocities would not be high enough to carry the suspended material very far out. Excavation to increase depth will not be authorized. Excavation of quantifiable sediment deposits above the. natural lake bottom would be considered,. as has been donI:! near the inlet in the past. The goal of the city should be to mimic natural hydrologic conditions, inasmuch as possible. This would mean that there would be fluctuating water levels, as in the past, with periods when the basin is nearly devoid of standing water. The goal is not to keep as much water in the - " .... -f '3 basin as possible, or as high as possible, or to maintain a narrow band of water level fluctuation. . ., I also believe I have stated, and may have written, the pernrlttable outlet elevation, based upon the rules, would be something as low as 745.7' (currently permitted), bas~d upon the documented runput elevation at. the time of application several years ago, to as. high as 747.0', the documented runout elevation when the OHW was established in 1977. It is interesting to note that WSB' s survey of the outlet channel last fall shows significant headcutting of the outlet channel from the dowristream end, but relatively little change on the upstream end. The runout control elevation in the 1999 survey was 745.73, whjle in 2004.it was 745.48'. These occur at nearly the same location. The 0:25' of difference is insignificant, and withllrthe accepted margin of error for surveying. In other words, the normal 'water elevation of Dean Lake has not changed between .1999 and 2004, contrary to what some would claim , , ~~. Patrick J. Lynch I Area Hydrologist c: Scott SWCD, Pete Beckius Lower Minnesota River Watershed District, Terry Schwalbe Prior Lake-Spring Lake Watershed District, Shannon Lottharnmer WSB & Associates, Todd Hubmer /' ~ .,.. 5. .""'.~~'~1Ui;l!'1 A ~II 't 701 Xenia Avenue South. Suite 300 Minneapolis, MN 55416 WSB www.wsbeng.com & Associates, Inc. April 8, 2005 .. _763.5414800.Fax763-541-1700 INFRASTRUCTURE I ENGINEERING I PLANNING I CONSTRUCTION Environmental Advisory Committee c/o Bruce Loney City of Shakopee 129 Holmes Street South Shakopee,~ 55379-1328 Re: Final Design of Dean Lake Outlet City of Shakopee, MN WSB Project No. 1281-83 Dear Mr. Loney and EAC Commissioners: This letter is intended to provide you with an update on the Dean Lake Outlet and to request-your con~ideration on providing a recommendation to the City Council for proceeding to final design. The City and WSB presented the current Dean Lake outlet proposal to the Lower Minnesota River Watershed District (LMRWD) at their last monthly meeting. We discussed the proposed design and any concerns which they may have in regard to this design. Attached is a copy of our correspondence to the LMR WD board. Based on conversations with the LMRWD board and others the following issues will be addressed during final design: 1. Operational plan for the Dean Lake by-pass channel 2. Stabilization of the Dean Lake Outlet Channel downstream of the proposed outlet location 3. Maintain the 100-HWL elevation in Dean Lake at 749.0 4. Outlet should attempt to - mimic historical outlet performance 5. Verify that septic systems will not be adversely impacted by the proposed outlet 6. Evaluate opportunities to improve the quality of water entering Dean Lake from the Prior Lake outlet channel. Furthermore, the City, LMR WD and the MDNR have received comments related to the OHW for Dean Lake. In regard to this discussion, please review the MDNR comments contained in the attachment. We request that the discussion associated with the OHW for Dean Lake not be confused with the establishment of the run-out elevation from the Lake. The run-out elevation of the Dean Lake outlet must occur between elevations 745.7 and 746.9 as determined by the C:\Documents '1I1d Settlngs'mthemigILocal SettlngslTemporary Internet FileslOLK9BlEllvironmental Advisory Commtttee.doc . 'A, G(-YL .i WSB I }-1S1 ,f:3 J --- & Associates, Inc. Infrastructure I Engineering I Planning 11 Construction 701 Xenia Avenue South Suite 300 March 8, 2005 Minneapolis, MN 55416 Tel: 763-541-4800 - Fax: 763-541-1700 . Mr. Terry Schwalbe, Administrator Lower Minnesota River Watershed District 200 4th Avenue West Shakopee, MN 55379 Re: Proposed Outlet Improvements for Deans Lake City of Shakopee, MN , WSB Project No. 1281-83 Dear Mr. Schwalbe: " This letter is wntten in response to your request for information about the permanent outlet structure being proposed for Deans Lake in the City of Shakopee. The key remai~ing issues, as they relate to the outlet from Deans Lake, appear to be the following: 1. The normal nm out elevation from the outlet structure at Deans Lake. 2. The proposed operational plan for the Deans Lake bypass. 3. As established by the Minnesota Department of Natural Resources, ordinary high water level of747:0. The City would like to provide the followirig information as it relates to these concerns: 1. The City of Shakopee currently has in place permits to construct a permanent outlet from Deans Lake at elevation 745.7 from United States Corps of Army Engineers and the Minnesota Department of Natural Resources. 2. The City of Shakopee in response to residential concerns has proposed to revise the run out elevation from elevation 745.7 to elevation 746.5. 3. The proposed outlet from Deans Lake will be designed to operate with a fluctuation between elevation 746.5 and 747.0 during the operation ofthe Prior Lake/Spring Lake outlet channel. 4. The currently proposed outlet structure from Deans Lake has a permanent nm out elevation Qf746.5 and an anticipated laO-year high water elevation of749.0. There has been much thought put into Deans Lake as it relates to the anticipated run out elevation and the 100- year high water elevation. The issues surrounding these elevations are as follows: a. All housing and developrnent adjacent to Deans Lake have been built over the years with an anticipated 100-year high water elevation of749.0. The City of, Minneapolis I St. Cloud K:IDIJ81_8JlMmiIlIDocsILTR - Iscl"",/I,. - DJD7DJ.t1oc Equal Opportunity Employer 'A.' LftL f ! ~lJ! rf3 WSB .4ZfJPiIoIl'%~lIn'If~ Infrastructure I Engineering I Planning I Construction 701 Xenia Avenue South & Associates, Inc. Suite 300 March 8, 2005 Minneapolis, MN 55416 Tel: 763-541-4800 - Fax: 763-541-1700 Mr. Terry Schwalbe, Administrator Lower Minnesota River Watershed District 200 4th Avenue West Shakopee, MN 55379 Re: Proposed Outlet Improvements for Deans Lake City of Shakopee, MN WSB Project No. 1281-83 Dear Mr. Schwalbe: " This letter is written in response to your request for information about the permanent outlet structure being proposed for Deans Lake in the City of Shakopee. The key remaining issues, as they relate to the outlet from Deans Lake, appear to be the following: 1. The normal run out elevation from the outlet structure at Deans Lake. 2. The proposed operational plan for the Deans Lake bypass. 3. As established by the Minnesota Department of Natural Resources, ordinary high water level of747.0. The City would like to provide the following information as it relates to these concerns: 1. The City of Shakopee currently has in place permits to construct a permanent outlet from Deans Lake at elevation 745.7 from United States Corps of Army Engineers and the Minnesota Department of Natural Resources. 2. The City of Shakopee in response to residential concerns has proposed to revise the nm out elevation from elevation 745.7 to elevation 746.5. 3. The proposed outlet from Deans Lake will be designed to operate with a fluctuation between elevation 746.5 and 747.0 during the operation of the Prior Lake/Spring Lake outlet channel. 4. The currently proposed outlet structure from Deans Lake has a permanent run out elevation of746.5 and an anticipated 100-year high water elevation of749.0. There has been much thought put into Deans Lake as it relates to the anticipated nm out elevation and the 100-year high water elevation. The issues surrounding these elevations are as follows: a. All housing and development adjacent to Deans Lake have been built over the years with an anticipated 100-year high water elevation of749.0. The City of. Minneapolis I St. Cloud K:\O I 18 I _83l<clm;nIDocsIL TR - Iscl",,"!!e - 030705."oc Equal Opportunity Employer Mr. TerrySchwalb~ March 8, 2005 II" Page 2 Shakopee requires that the adj acent structures maintain 3- feet of freeboard between the building opening and the anticipated 100-year high water level of Deans Lake. Increasing the 100-year high water elevation of Deans Lake could increase the flood risks to properties adj acent to the lake. b. Should water elevations exceed 749.0, there is no available emergency overflow to handle storms in excess ofthe 100-year event. TH169 does not overtop until approximate elevation 752.0. Therefore, reducing the allowable freeboard between the 100-year high water elevation and the adjacent homes could result in significant damage for extreme storm events, such as the event ofJuly 11,2000 when ll-inches ofrain fell in Eagan. c. The current nm out elevation from Deans Lake has been chosen such that it will not adversely affect vegetation adjacent to Deans Lake. An elevation above 746.5 may impact existing vegetation and habitats surrounding Deans Lake. . 5. The City of Shakopee proposes to split the flow of the Prior Lake/Spring Lake outlet channel, thereby allowing the base flow discharges from the Prior Lake/Spring Lake outlet channel to be discharged both into Deans Lake and also through the bypass structure. This will supply adequate water to meet the hydrologic needs ofboth wetland complexes. The propo~ed discharge rates to both Deans Lake and the bypass will be provided on submittal of final design documents for your review. 6. Attached for your information is correspondence from the Minnesota Department of Natural Resources as it relates to the discussion ofthe ordinary high water level at Deans Lake. The City has not expressed any desire to request additional reviews of the ordinary high water level for Deans Lake.. We would like the opportunity to discuss these issues and any other issues the Lower Minnesota River Watershed District may have as it relates to the preparation of final plans for the construction of a permanent outlet structure from Deans Lake. We will be present at your March 16, 2005 meeting. to review these issues with the board. If you have any questions, please feel free to contactme at 763-287-7182. Sincerely, WSB & Associates, Inc. 7~ ;/ "'~?~ Todd E. Hubmer, P .E. Proj ect Manager Attachment cc: Bruce Loney, City of Shakopee tsh K:\Ol ~SJ_83\Admill\Docs\LTR - (schwa/he - 030705.doc <' . } . Minnesota Department of Natural Resources t)t,Jd'~':C,1" , Central Region Waters - 1200 Warner Road~ St. Paul, MN 55106-6793 . Telephone: (651) 772-7910 Fax: (651) 772-7977 "0"" ~TD 'l 0 /.. jll) ICD .l.. u, V U:" t'l !(~ l., <i:; $::t'v" '.~ .~:'r '. \ ~;:. a \1 ~) lJ ~..A H';:<?;'." "t"" February 8, 2005 Bruce Loney City of Shakopee 129 So. Holmes Street Shakopee, Minnesota 55379 ,-i" RE: Dean's Lake (#70-74P) , , Dear :Lvll:. Loney: As you requested, I cut and pasted several past e-mails regarding Dean's Lake, its long standing Ordinary High Water Level (OHW), and permissible runout level. To date, there are only a few individual property owners on the south side of the basin that continue to question the OHW that was established, then.revisited twice, by DNR. None of the units of government irivolved in this matter over the years have expressed reservation about the OHW that was established, or the methodology used to arrive at the elevation. I anticipate that I and one of our surveyors will continue to shoot the water surface elevation and reset the lake gage every spring.' We now also have a regular gage reader on the lake that submits lal<.e level readings for inclusion in our statewide database. From: Pat Lynch rmailto:oat.lvnch@)dnr:state.mn.usl Sent: Monday, October 18, 2004 1:15 PM To: Bob Potocnik Cc: BLonev@)ci.shakooee.mn.us; Glen Yakel; John Scherek; Mel Sinn Subject: Dean Lake Benchmarks, Basin #70-74P I met last week (October 11) with a survey crew from WSB & Associates to have them shoot elevations at a number of locations around Dean's Lake in Shakopee. WSB was working on behalf of the City of Shakopee.The WSB surveyors had GPS-based equipment. Relevant findings were .as follows, and in 1929 datum: LakesDB describes a DNR benchmark as Elevation: 761.69 ft, Date Set: 02/27/1980 . Datum: 1929 Benchmark Location Township: 115 Range: 22 Section: 15 Description: A 60d sp[ke in the north side of trans. pole on south side of road in Haworth yard. I found this BM last week. The Haworth's stil/live there. WSB obtained an elevatiOn of 761.69', exactly as we set it! We have an obwell (#4) on the Czaja property on the southwest side of the lake. This was located and shot at 755.02' last week. We have it at 755.04' in our records. ~ I had them shoot a WSE for Dean Lake near oLlrlak~ gage. They shot 746.25'. I read 746.15', based upon our temporary' staff gage. DNR Information: 651-296-6157 . 1-888-646-6367 . TTY: 651-296-5484 . 1-800-657-3929 All Equ,,1 UPPOrlUllily El11pllly~r -C-. Prilll~t1111l I{~~y~ktl P"p~r Clllll"illill~ " ~ Millilllulll 01" 20'A PtlSl-COIlSulller W"ste . ';. ,:,~ 'c The north rim of the sanitary sewer manhole cover near our lake gage was shot at 755.75'. I believe we have it at 755.6'. , I was quite satisfied with the findings. At least when the city and DNR are discussing elevations, we know we are comparing apples to apples. Several locals swear the water level in the wetland is lower, in general, than it has been in past years. The WSE last week is 0.38 of a foot below. the average water level based upon recorded levels reported in LakesDB. This is no surprise, since a significant contribution to the Deans Lake hydrology is from the Prior Lake outlet, . which hadn't been outletting since July 19 ofthis year. We (the city and me) are still looking at the outlet on the north side of the lake to see if our suspicions about the outlet being lowered by erosion arid scour are true. The sandy soils and high discharge when Prior Lake is outfetting through Deans Lake provide conditions conducive to downcutting of the channel. Thanks a lot for all your help with this. I really appreciate it. I Please place a copy of this e-mail in the Dean Lake file at Central Office. ----Original Message----- From: Pat Lynch rmailto:oat.lvnch(o)dnr.state.mn.usl Sent: Tuesday, August 03, 20046:27 AM To: blonev@)cLshakooee.mn.us Subject: Fwd: Re: Dean Lake (70-74P), Scott County I forwarded all the relative e-mails that I have seen the last 5 weeks to thE7 supervisor of the group wl:1o performs the OHW investigations for the state.. Below is the response I got to the inquiry about the Dean Lake OHW. It appears to support my June 30 e-mail to you and Mr. Leek. >>> Glen Yakel 8/2/04 4:39 PM >>> Pat -- I have reviewed our field survey information for Dean Lake. The OHW was determined by the Hydrographics survey crew in September, 1977 to be , at elevation 747.0, and is based on the best available vegetation growing around the perimeter of the lake. Recorded spring lake levels range as much as a foot above the OHW, which is not an uncommon occurrence for a M'innesota lake. Also, the most recently determined runput elevation for Dean Lake is at 74S.7, or 1.3' below the OHW, which compares favorably to the OHW. The few lake level readings on file show a lake fluctuating both above and below the OHW - typical for a Minnesota lake. Nothing ill the record indicates that the OHW for Dean Lake, which. has been used by the City of Shako pee since 1977, is incorrect. Glen Yakel Hydrographics Supervisor DNR Waters (651) 296-4805 alen. vakel(Ci)dnr .state.mn.us From: Pat Lynch rmailto:oat.lvnch(O)dnr.state.mn.usl Sent: Wednesday, June 30,200412:02 PM To: blonev(O)cLshakooee.mn.us; MLeek(O)ci.shakooee.mn.u5 Subject: RE: Dean Lake development gentlemen: Thank you for including me in your correspondence. Seems once every year or so I have to go over the history of Dean Lake, as our files /'. " would have it. It is a shallow water table wetland that historically was provided its hydrology from the water table (surtidal) aquifer. This was verified by DNR studies in the early 1980's and mid-1990's, when some thought the Shiely quarry dewatering would dry the lake up; it never did. Pumping from the buried bedrock aquifer has little to no effect on Dean Lake. Information from 1978, when DNR identified the wetland as being of the size and type to be regulated by DNR, notes on the field data sheet indicate Dean lake CIS n a marginal type 4 wetland, subject to drying out. n It further. indicates the basin had an average depth of3.Sfeet and a maximum depth of 5 feet. It indicates that annual water level fluctuations of 2-3 feet were normal. The 1954 USGS quad map has a ,water elevation of 746. the 1901 quad, while not showing a lake elevation, shows a small open-water area surrounded by considerable emergent wetland fringe. DNR established the OHW of Dean Lake based upon long standing procedures. Based upon the physical water level indicators (hard and " softwood trees, ice ridges, stainS on trees and boulders, etc.) visible. around the wetland, an OHW of 747.0' was determined. This is not a normal water level; average water level, .or high. water level.. It is not based upon any statistical analysis of water level readings. It is ;. purely based upon the physical evidence left on the landscape. It does not define the edge of wetland. 90% of the time, a delineated wetland edge w!1I be higher in elevation than the OHW. This is certainly the case at Dean Lake. I looked at the water level data we do. have for the lake. It is available to anyone on our web site. 'we have data, off and on, back to the late 1970~s, with some gaps in the 90's. for all the readings, the average water level is746.52'. This spring (April 19, 2004) when I surveyed it, the level was 746.17'. These elevations are very much in line with an OHW of 747'. I also looked at air photo on the Scott County website. Photos from 2000 and 2003 have a large percentage of the wetland in open water. If you look at quads and photos before the Prior Lake outlet was opened and before the wet 1980's and 1990's, the amount of open water was considerably less. Truth is, the wetland would be of higher ecological value if it were 2-3 feet deep. That would be more benefidal for waterfowl and furbearers, less condudve to rough fish survival, and would likely result in greater vegetative diversity. The Prior Lake outlet provides a lot of the hydrology to the lake now. Coupled with an inefficient outlet (it meanders through the floodplain forest and type 2 wetland), the additional hydrology from Prior Lake and fluctuations in water table elevation, it comes as no surprise that the surface water elevation of Dean Lake fluctuates. Nothing about the water levels 1 have observed have been alarming or'surprising to me. I am comfortable with the OHW of 747.0', and see no reason to revisit it. The outlet structure, yet to be constructed, has been discussed extensively. It was permitted, following the required review process by the DNR, watershed district, SWCD, etc.. I have no time to go back and revisit that matter unless the city sees some compelling reason to do so. As far as trespass, I can't address that. As Michael indicates, it depends on who owns the bed, whether or not it is navigable, whether it is posted, or permission granted, what activity one is engaged in. - Regarding the cattail and algae concerns, I suggest that folks from the .DNR aquatic plant management program be contacted with any questions or concerns. They work out the DNR Fisheries office here at 651-772-7950. Hope this helps, at least a bit. Feel free to pass this info along to anyone who may be interested. Pat Lynch I ., ',. ---Original Message----- From: Pat Lynch rmailto:oat.lvnch(1ildnr.state.mn.usl Sent: Thursday, September 09, 2004 7:58 AM To: aweber@)ci.shakooee.mn.us; BLonev(1ilci.shakooee.mn.us; JSwentek(1ilci.shakooee.mn.us; JWevandt(filci .shakooee. mo.. us; MLeek@)ci.shakooee.mn.us; MMcneill(1ilci .sha kooee. mo.. us; MThemio(filci .shakooee. mn.us; tmeiller@)ci.shakooee.mn.us; oshutroo(filco.scott.mn.us; k oerl(filhotmail.com; terrvs(fillowermn.com; slotthammer(filolslwd.orq; ematthiesen(1ilwentk.comi smenden(filwenck.com; AMoffatt(filwsbeno.com; Thubmer(filwsbeno.com; thubner(1ilwsaena.com Subject: Re: Dean Lake Outlet Mtg Bruce, et al: , Thanks for hosting last week's meeting. I hope all came away with a , better understanding of the regulatory, environmental, hydrologic and engineering issues associated with water level management at. Dean's - . . Lake. A couple things in Ms. Gerlach's recent e-mail need to be clarified right away; items'#l and #3 and #4, in particular. 1. The outlet elev<ltions. Further surveying to tcJke pl<lce. Consideration of adjustments to higher levels (747 or 748) to e,nsure maximum retention of water that is conveyed into Dean I<lke, by whatever me.ms. All agreed additional survey work, particularly a profile of the outlet channel and identification of the current runout control elevation.. A normal water level.(runout elevation) above 747' is not allowable under the laws and rules we are bound by. There is nothing in the record that . suggests the basiri maintained a normal water level. above747 historically. What the rules say are this: WATER LEVEL CONTROLS. Subpart 1. Goals. It is the goal of the department to manage public waters to: .f A. maintain or restore natural flow and natural water level conditions tothe maximum feasible extent; B. encourage the construction of small off-channel retarding structures for the conservation of water in altered, natural waterbasins, consistent with any overall plans for the affected watershed area; and C. limit the artificial manipuiation of water levels, except when the balance of affected public interests clearly, warrants the establishment of appropriate controls and it is not proposed solely to satisfy private interests. They also say: Subp. 3. Prohibited water level control facilities. Construction or reconstruction of water level control facilities is prohibited when it is intended to manipulate water levels solely to satisfy private interests. Further, they say, F. the construction or reconstruction of water level control structures or changing the level of an existing structure shall be approved only to: (1) control and store flood watersi (2) maintain low flows for instream flow or water . ',' . . ~ level protection; (3) manage water quality, including the prevention or control of;erosion and sedimentation; . (4) improve water-based recreation; (5) create, improve, and maintain water supplies; (6) create, improve, or maintain aquatic habitat for fish and wildlife species; (7) establish, improve, or maintain the generation of hydroelectric power; or (8) restore the existing control elevation to a historic natural water elevation if detailed engineering surveys establish that the proposed control elevation does not exceed : the estimated natural control elevation; In particular, read the goals_l.tbefirst part of the l1,l!es I included < '~.' . .' -. ,... ." "If .. above). 3. Acknowledgment and consideration of the petition by lakeshore owners to set the ordinary high water level at 748' accepted and recorded by the City -1984. Study and consideration of recent challenges to the set OHWL of 747' made by west end lakeshore owners. I don't understand where the disconnect is between me and some on the OHWL. It is not set by petition. It is based upon the physical water level indicators on the landscape. In the case of Deans "Lake, it was determined to be at 747. That elevation was reaffirmed when our surveyors revisited the lake in 1983. As our webSjite states, "The Ordinary High Water Level (OHWL) is a term that many lake, wetland, and river property owners hear, but it is often misunderstood. . What the OHWL is NOT: - a runout elevation - an average water level - an extreme high water level - an arbitrary elevation set by an individual, group, or agency . The OHWL has no significance with respect to private ownership of the underlying bed. My suggestion to the dty is to not spend a lot of time on this one, instead, focusing on the appropriate control elevation. The runout elevation that is currently permitted, or which may be modified under permit, has absolutely no bearing on the OHWL, nor does the OHWL have any bearing on the r!lnout elevation. 4. Development of vision and purpose for Dean Lake in light of the many changes engineered in the last 20 years 'and the new plans for significant residential communities, trails, and parks adjacent to this 250 acre lake. Reasearch into aquatic weed control, further dredging and water quality. If the thought here is removal of sediment near the mouth. of the Prior Lake channel where it enters Deans Lake, I am ok with that. There is very little likelihood that sediment is carried very far i"n to the lake-proper. The velocities would not be high enough to carry the suspended material very far out. Excavation to increase depth will not be authorized. Excavation of quantifiable sediment deposits above the. natural lake bottom would be considered,. as has been done near the inlet in the past. The goal of the city should beto mimic natural hydrologic conditions, inasmuch as possible. This would mean that there would be fluctuating water levels, as in the past, with periods when the basin is nearly devoid of standing water. The goal is not to keep as much water in the . -, '.; i basin as possible, or as high as possible, or to maintain a narrow band of water level fluctuation. ~ I also believe I have stated, and may have written, the permittable outlet elevation, based upon the rules, would be something as low as 745.7' (currently permitted), based upon the documented runout elevation at. the time of application several years ago, to ashigh as 747.0', the documented runout elevation when the OHW was established in 1977. It is interesting to note that WSB's survey of the outlet channel last fall shows significant headcutting of the outlet channel from the downstream end, but relatively little change on the upstream end. The runout control elevation in the 1999 survey was 745.73, wh).le in 2004 it was 745.48'. These occur at nearly the same location. The 0.25' of difference is insignificant, and within the accepted margin of error for surveying. In other words, the normal water elevation of Dean -Lake has not changed between .1999 and 2004, contrary to what some would claim. : ~ Patrick J. Lynch I Area Hydrologist c: Scott SWCD, Pete Beckius Lower Minnesota River Watershed District, Terry Schwalbe Prior Lake~Spring Lake Watershed District, Shannon Lotthammer WSB & Associates, Todd Hubmer /' ------ _ .----.-..- - ---- ,--- ~--~.._~- ~ -- 4____._~__~___~___~___.__~~_~_~__~__~..__.___u.____.,.......~ -- _ _ ---._ __ '_ __,~_____:_____-__._,_____ _~~___ _ ,_~_,.___~______.._ --'-----_~ __,__~__~~_____ _ ___, _ _ ,____ _______._u_ _ _,__ ~.___~~___ _ ___~~__ ~__ _ _ >_____.___ _ _ __'________... _ _ _ _ __~____'______.___~_.~.___ _ _ _ _ _, __ __.__________-----, - ----- - -- -- - - DEAN LAKE OUTLET CHANNEL SURVEY ~ T H 1 69 E X 1ST. 1 2 I X 6 I BOX C U L V E R T LEG END i~ INV. ELEV. - 741.5 1999 SURVEY r · ELEV. 744.15 ~ ~ 2004 SURVEY I ~ · 'ELEV. 741. 721 ; - ~ I ELEV. 7~5.22 5 ~~ I ~ ^.~ ELEV. 7[5.73 Ii: 0 ELEV. 7~5. 32 ELEv. ,f i~i.. -r--- ELEV. ~~~ : r. r\l ,I"" on ELEV. ~5!i =r=ELEV. 7~4.89 ~H ~ >-m..... .... " 0 0 ,ELEV. 7~5. 70 Ui Q 1.- I o 200 400 BENCH MARK ELEV 755.0~ BENCH MARK ELEV 761~ ~.5..s TOP OF 06. WELL NO.4 SPIKE IN NO. SIDE OF TRANS. PP C ~ s; NVGD 1929-1988 ADJ. I SO. SIDE OF ROAD IN HAWORTH YARD = Cl 1) NVGD 1929 -1988 ADJ. r:rJ. ;;., ~ - ~d ~ ~ .;:< _ l. ~ .. = ~ . : . . . . , . . = r:rJ. 752.51999 S:rREAM:LENGTH-2750 FEET 752.50""1' 1) ~ C 1) .20QLr SJREAM LENGTH. -:'24"80 FEET .; ~ g. ...:l ~ 750 750 = ~ ~ ~ 0\ r:/) ~ 0\ ~ 0\ ..... 747.5 747.5 STREAM PROFILE: 745 745 200LlSTREAM: PROFILE ~8~ R 742.5 742.5 ~~:g ~ J:':;z 10 a;CJ)~ :Z '~,g ~ <ll "- u. 740 . 740 ~ ~ .....v.. . 0 c 5 ~ o '" v 737.5 737.5 ~ 1!' 735 .j r.t ~.~ ~ ....~. :.~ ~.~ .....: ~..~ :i .~:..~ .~..~ .~..~ .~. .~:: .~.~..~.~ .~ oo'~ 00' '^ ~8 r; ~..~ ~ . .ri r .~.. ',; r.~ :..~ 735 ....~IJ: '1jo~oo . <),;00 52'00 5)-'00 5,(;60""' <5.';;"'00 '"" "56~O<j"" "5"7;.6'0' '58-00 59"00 60"00 bl'OO bl"OD"' 63.00" 61l."00 E>':iI-QO 66;'00 67..00 66..00 6.')"00 70..00 7l'00 /2..00 '3',)0' (1I..oO 75.00 16+00 11+-00 /8<-00 ~ '0':0 ., '..)J .', ,;>.;., . ~'.--:, . '^.,~" : "~.:',, · ~ jo .1 ~L . l ''"'~''';'' .: ,.oL' . l ":'J ::: ?:~-v J,. ~ .,'~. .; ,;:~;(' · ~ .,;~) . ~".:" ::,.~. .J', ;:<.1:~' . z,,:, . ~ ...~'. ~ ,:..::,: : ~ "." "'J, "..0:' --- --- -- --- .-- - --- - - - '--. --.J I I I - .- -