2023/12/15 - OTHER - (NA) - Correspondence

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• Towne, Jason From: Druffner, Jacob D - DNR <jacob.druffner@wisconsin.gov> Sent: Friday, December 15, 2023 1:55 PM To: Cronk, Amy L - DNR Cc: Towne, Jason; Rafajko, Sarah L - DNR Subject: Spirit Lake Road Attachments: RE:W. Spirit Lake Rd. over Spirit Creek, Town of Trade Lake, Burnett County Hi Amy, After further discussing this project internally, I am satisfied moving forward without an H&H.This decision is specific to this crossing and is not applicable to all upsizes of structures within Zone A floodplain. Ultimately the County is the permitting authority for the floodplain project,and they are able to request a study for their records if so desired under Sec. 22-55 and 22-90. 1. The crossing does meet the below section of the current DNR Model Floodplain Ordinance. MUNICIPALITIES AND STATE AGENCIES REGULATED Unless specifically exempted by law, all cities,villages, towns, and counties are required to comply with this ordinance and obtain all necessary permits. [....] If a local transportation project is located within a Zone A floodplain and is not a WisDOT project under s. 30.2022,then the road project design documents(including appropriate detailed plans and profiles)may be sufficient to meet the requirements for issuance of a local floodplain permit if the following apply:The applicant provides documentation to the Floodplain Administrator that the proposed project is a culvert replacement or bridge replacement under 20' span at the same location,the project is exempt from a DNR permit under s. 30.123(6)(d), the capacity is not decreased,the top road grade is not raised, and no floodway data is available from a federal, state, or other source. If floodway data is available in the impacted area from a federal, state, or other source that existing data must be utilized by the applicant in the analysis of the project site. 2. I did previously state: "The increased hydraulic capacity of the proposed culvert could cause an increase to the base flood elevation on the downstream side of the crossing on private land outside of the Town ROW." While increases are possible downstream of a culvert with larger capacity,the likelihood that the increase would occur much beyond the cross section at the outlet of the culvert is not very likely given that the next downstream cross section (#1 in attached photo) will be dictated by further downstream cross sections. i.e. the changes in water surface elevation downstream of the crossing are fairly localized and would, with confidence due to the relative upsize, not trigger FEMA requirements (>_1.0 ft increase in Zone A). 1 / ' f 0 3 Z22,- Off. (` 101- ' q v• dr 3q6 07 1