HomeMy WebLinkAbout20220235 131 Excelsior North Spring Run Special Use Permit Stormwater/Groundwater Impacts Lcm)
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October 25. 2O22
MorkTorpey Planning Board Char
City of Saratoga Springs
474Bmadwoy
Saratoga Springs, NY1280G
RE: North Spring Run—8tormwator/GmundwoterImpacts
131 Excelsior Avenue, Saratoga Sphngs, NY
Oaer Mr. Torpey.
This letter is to summarize the proposed North Spring Run project in relation to the Loughbany Lake reservoir. Existing
conditions of the site includes e former Brewery with associated parking and truck loading onaao. 8tonnweter runoff from
the northern and eastern portion of the site is collected in o closed drainage system and piped to the existing drainage
channel along the western portion of the property. Runoff from the western portion of the property generally sheet flows
to the same drainage channel. The drainage channel flows south through (2)six-foot diameter culverts under Excelsior
Ave, and ultimately discharges to Spring Run.
The developed portion of the project site is approximately 230' south of LoughbenY Lohe'o normal water elevation.
Finished grade of the site ranges from 270'to 275'. with the drainage channel along the western portion of the parcel at
255' Booed on an"Engineering Assessment Report ofLoughbnnY Lake Dam" prepared by 8ohone| Engineering. doted
September 15. 2016. the nomne| pool elevation of the lake is 283.4' Therefone,the site is approximately eight to thirteen
feet below the lake. 8tonnwater runoff from the site will be collected and discharge to the existing drainage channel along
the western portion of the site and flow south away from the lake. Based on the elevation of the site and drainage outfaUa,
surface runoff from the project would not impact Loughbony Lake.
As port of the North Spring Run project, Tarnsoon Consultants completed o gaotaohnioa| investigation and report, titled
^0eoteohnioa| Engineering Report"and dated December 31, 2010. for the site. As part of the report Tarnaoon developed
general characteristics of the subsurface conditions based upon their review of the subsurface exploration nyou|ts,
geologic aatting, and their understanding of the project. Regarding groundwater the following is an excerpt from their
report: "Groundwater observations and measurements were made as the bonoho|oo were completed. 8000d on these
measurements and the recovery of wet soil samp|ea, it appears that groundwater was present below the depth of about 7
to 10 feet across the eastern and central portions of the site at the time of inveatigation,this indicating groundwater
surface elevations in the range of about 264 to 206 feet, and sloping downward to the weot.^ Based on the geoteohnioo|
investigation and report, groundwater from the site would flow west towards the drainage ohonne|, and not north to
Loughberry Lake. Additiona||y, runoff from the impervious portion of the site will be collected in a closed drainage system
and discharge to the western drainage channel.
Based on the project site elevation being located ba|ovv Loughbarry Lake and groundwater otthe site flowing waot, the
proposed project would not adversely impact quality of Loughbarry Lake water. Additionally, removing the previous
industrial use and currently untreated atormwater runoff, the proposed project should provide an improvement towater
quality to the existing drainage channel and groundwater.
8inonne|y.
,_L bL
Douglas Heller, PE
Associate Principal/Civil Engineer