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HomeMy WebLinkAboutAdditional Info 13. 0971 Bob Hutchins ( From: Sent: To: Nate Albers <nate@basecampservices.com> Friday, October 25, 2013 3:04 PM Pete Young Cc: Nathan Briese; Skancke,Jennie (DNR); Bob Hutchins Subject: Re: Hydrology/Engineering Calculations Thank you for sending this.I will have this checked out and I really hope their plan works for all involved.The water quality of the lake has gotten so bad that we have been considering selling and spending our summers elsewhere.I am happy to hear some changes are being made to Spring Lake so hopefully that will help improve the water quality as well.Thanks! Sincerely, Nate Albers Cellular(561)723-3003 Office 888-347-2789 www.TentLogix.com www.BaseCampServices.com On Oct 25,2013,at 2:51 PM, "Pete Young"<pyoung@cityofpriorlake.com>wrote: >Mr.Albers, >The engineering/building department and public works staff reviewed the site plan and engineering calculations for the home proposed at 16270 Park Avenue SE in Prior Lake.The City requested calculations to show that water will be properly managed through the site.The applicant was required to: 1)Show that the proposed project will not impact other property owners in the area with respect to changed runoff patterns;and 2)Show that the proposed project is designed to convey the water down the slope without causing additional erosion or increasing the sediment load to Prior Lake. >The calculations and site plan submitted by Greg Halling,PE,(attached)show that the proposed drainage swale has the capacity to handle expected the flows from the small contributing watershed and not overflow onto adjacent properties during large rainfall events.Because the lot is steep,the applicant is proposing to line the channel with rock(Manning's n=0.40,typical value for cobble/gravel channel). The applicant has also proposed to install a sediment basin at the top of the swale as well as another vegetated depression within the swale(called a raingarden on the site plan,but this area is more likely to function as a vegetated swale and secondary sediment basin).Based on the site plan and calculations submitted,the applicant's plans have satisfied both stormwater management requirements set forth during the building permit process that are listed above.It appears that controlling the runoff in a properly-sized swale,rather than letting the runoff flow over the steep lot uncontrolled,will actually reduce the amount of sediment entering the lake from this property after the new home is built.Before construction started,the property had sand/gravel deposits near the lake that appear to have been created at least partially by erosion from the private gravel roadway(Park Ave SE).Although the City does not control or maintain this roadway,the City recommends that the residents have it paved to reduce the amount of sediment entering the downslope properties in the area.The gravel is already considered an impervious surface,so paving would not increase runoff volume over existing conditions,and paving would greatly reduce the potential sediment load entering Prior Lake. > >In addition to installing permanent stormwater management features,the applicant also must control potential erosion and sedimentation during construction;two rows of silt fence are required between the disturbed area and the lake,and unworked areas must be temporarily stabilized after grading is complete in each area.The City will be inspecting this property to ensure that proper erosion/sediment control practices are being installed and maintained. >Thank you for sharing your concerns about Prior Lake and this ongoing construction project.I've copied the DNR hydrologist for our local area so that she is also aware of your concerns. > >Pete Young,PE,CPESC >Water Resources Engineer I City of Prior Lake 1 >4646 Dakota Street SE I Prior Lake,MN 55372 >952-447-9831 I [fax] 952-447-4245 > > > Original Message >From:Nathan Briese >Sent: Friday,October 25,2013 10:42 AM >To:Pete Young >Subject:FW:Hydrology/Engineering Calculations > > > Original Message >From:Nate Albers [mailto:nate@basecampservices.com] >Sent: Friday,October 25,2013 10:36 AM >To:Nathan Briese >Subject:Hydrology/Engineering Calculations > >Good morning Nathan. As discussed yesterday please send me the engineering calculations and related documents regarding the development at the adjacent property.I need to have our civil engineer review these to ensure my property and the lake will not be further damaged by this development and the related run-off.I will also be sending these to the DNR for review as my previous concerns that have been presented to the City of Prior Lake in regards to the negative effect this property has had on water quality have gone unreturned and corrections have not been made to alleviate damage to the lake.I have no issues with the someone building at the site but that should not negatively effect my property and/or other properties not should it reduce the water quality of the lake.I have sent photos and video previously but I will send to you as well so you are able to see the extent this property has affected the lake.Thank you for your time. > >Sincerely, > >Nate Albers >Cellular(561)723-3003 >Office 888-347-2789 >www.TentLogix.com >www.BaseCampServices.com > > ><16270 Park Ave SE-site plan.pdf> ><16270 Park Ave SE-DA sketch.pdf> ><16270 Park Ave SE-calc overview.pdf> ><16270 Park Ave SE-swale capacity.pdf> 2 Bob Hutchins From: Lamont Steinwand <lamont@avidbuildersmn.com> Sent: Monday,August 05, 2013 11:55 AM To: Bob Hutchins Subject: FW: Estimate xxxxx Park Ave SE, Prior Lake Hi Bob, This was some continued ideas I had with Greg. Lamont ((2 r 366 _ A I ( O Original Message From: Greg Halling[mailto:grhalling@hallingeng.com] Sent: Thursday,July 25,2013 10:36 AM To:Lamont Steinwand Subject:RE:Estimate xxxxx Park Ave SE,Prior Lake I would think that could be made to work. However,with this being a gravel drive coming down the rain garden will need a lot of work to keep it operating as it will plug up quickly with sediment. 2444.does have a little sediment trap that could work on the front end of the rain garden. Go to http://www.rainguardian.biz/to check it out. Original Message From: Lamont Steinwand[mailto:lamont@avidbuildersmn.com] Sent: Thursday,July 25,2013 10:19 AM , ISI G To: Greg Halling ''` W Cc:Jeff Young V" Subject: RE:Estimate xxxxx Park Ave SE,Prior Lake01(1 Greg, / Is it possible to accomplish the same results with a manmade pond or rain garden in lieu of a catch basin. And,a river rock from that to the lake? This would be part of our landscape design. Would run down just inside property line. Lamont Original Message From: Greg Halling[mailto:grhalling@hallingeng.com] Sent: Wednesday,July 24,2013 3:40 PM To:Lamont Steinwand; s.swanson@integraonline.com Subject:RE:Estimate xxxxx Park Ave SE,Prior Lake Here is a draft of my review. Please review and let me know if you have any concerns or if there is something else that I overlooked or that you want specifically addressed. Original Message From:Lamont Steinwand[mailto:lamont@,avidbuildersmn.com] Sent: Tuesday,July 23,2013 7:18 AM To: s.swanson@integraonline.com Cc: Greg Halling Subject: RE:Estimate xxxxx Park Ave SE,Prior Lake Hi Greg, Any update on this project yet? 1 Prepared by: Gregory R. Halling, PE Date: July 23,2013 For: Proposed home construction at L 15& 15, Lakeside Park I have reviewed the proposed survey for the new home being built on the north end of Park Avenue on lots 15 and 16 of Lakeside Park. The proposed garage floor elevation is 920.2 and there is about 24"of slope proposed from the garage to the south. Almost the entire length of Park Avenue plus a portion of the 6 driveways and homes that are served by Park Avenue drain along the east side of the existing gravel drive towards the lake and this proposed home. The drainage area is approximately 0.17 acres of impervious surfaces and .08 acres of grass. Due to the steep grade on Park Avenue,the peak runoff will be based on the peak rainfall rate off the impervious rather than a 6"24 hour storm over the entire area. A short 15 minute burst of rain is likely to create the greatest rate of runoff. A 100 year storm event of 30 minutes is 2.5"of rain. On the MnDOT hydrograph peak rates of 10"per hour can be attained for small durations on drainage areas with times of concentration of 5 minutes. This type of rainfall should be used to determine peak rates of runoff. This equates to a runoff rate of Q=CIA or Q= 0.times 10.0 times 0.25 equals 1.6 CFS. We can expect greater rates with short bursts of rain. Almost all of the water appears to be directed to the east around the home. There will be a high potential for erosion around the side of the home. Since the water has primarily been directed through this lot historically,the home should be designed to convey the water along the lot line on the east side of the home. It is recommended that there be some sort of structure to catch this runoff and direct it around the home. Due to the slope, it is necessary to design a berm or wall to keep the water from going to the east rather than through the pipe. A catch basin or flared end should work. A 12"storm sewer can readily handle the calculated storm. The swale draining to the east should also be reinforced with a geotextile fabric with the grass growing through it. It is my professional opinion that the home as proposed will not be adversely impacted by the storm water coming down Park Avenue towards this home. Recommendations: 1. Raise car turnaround area and add a wall so there is a flat area to turnaround in. 2. Add a Flared end or catch basin with a 1.5' plus wall or berm to catch the runoff from Park Avenue. 3. Construct storm sewer along the east line of the property to carry the water down to the lake. 4. Add a treatment mechanism to treat this storm water prior to entering Prior Lake. The storm water has previously ran through a section of grass thereby cleaning the runoff prior to going into the lake. 5. Reinforce the constructed swale to prevent it from washing out. Scott,County Page 1 of 1 14 /1 ° � rte -- t i,,.-) ( „.. s ` l ' ,d' ��. �. � r F t _ r ' .-- ,/ '/ fj , /,/ . , , , '„,,_ ,, „.„. , _ , . , / --- , ) . f „„.., ,/.11 --, -Z.,-.,_____ / ',,„, �� { ii:/. - ' ,Li) ._.....\___,;, , r 18- - r .:1 „:,,,,,,,_:._,,,,. ,,,, _:,,,-, -14030-19-Is::: � 5: 1//, ' f 6 .. J / / / , 1 i.„ , 1\ ,�� \ '631° ( - _”- `42---*__"_,_` 1k,, - PLE, sa '' \\\*' 'A, ii, i\„,:\ .\\\\\ '1 -------__, ..,„ ,,,,, „ ;, , \ „..„3., J -- _ N„.. .. IMO_ 7 ti� Je-`� t 1e354 IIS t Park Avenue i This drawing is neither a legally recorded map nor a , survey and is not intended to be used as one.This drawing is a compilation of records, information,and / ' bS a 4M,4 data located in various city,county,and state offices, A ; and other sources affecting the area shown,and is to be ', NI • '_ .4*-:11 used for reference purposes only. Scott County is not JA A responsible for any inaccuracies herein contained. If W l 1111 P. discrepeancies are found,please contact the Scott County Surveyors Office. 8July 23, 2013 http://gis.co.scott.mn.us/servlet/com.esri.esrimap.Esrimap?ServiceName=overview&Client... 7/23/2013