Agenda - Council - 01/26/2021 - Laserfiche WebLink

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Available years of Farm Service Agency (FSA) aerial photography were reviewed for the site to determine long-term hydrology. In cases where additional aerial photography was relevant, available, and necessary to make hydrology determinations, we reviewed aerial photography from other sources such as the Minnesota Geospatial Information Office (MnGEO) and God Earth. Signatures at locations of potential wetlands on aerial photographs were interpreted and classified using seven codes (Table 2). Table 2. Aerial photograph interpretation codes Code Classification CS Crop stress DO Drowned out NC Not cropped SW Standing water WS Wetland signature AP Altered pattern NV Normal vegetation This analysis used only aerial photographs taken following periods of precipitation within the normal range as determined using the Wetland Delineation Precipitation Data Retrieval tool (Minnesota Climatology Office 2015). This tool classifies antecedent precipitation as Normal (N), Wet (W) or Dry (D) by comparing precipitation during the three months preceding the estimated date of aerial photography to the 30-year average from 1981-2010. Results Available aerial FSA photographs from the 5 most recent and available normal years (1995, 19961 20081 2010, and 2015) were assessed. Photo years were assessed for wet/normal/dry climatic conditions using the Wetland Delineation Precipitation Data Retrieval tool using a date of July 1. Areas showing at least a wetland signature for a recent Wet year (2013) were included in the aerial review. The review areas are shown on Figure 7. The Wetland Hydrology Recording from Aerial Imagery - Recording Form, photos of each Review Area, and FSA photographs for each year of review are included in Attachment C. Based on the results of the offsite hydrology review, none of the areas warranted field review. However, sample points (Attachment D) were taken in Areas A and C for documentation of field conditions. Both soil points lacked hydric soils and contained high amounts of sand throughout the soil profile which likely precludes these areas from ponding/holding water for more than 14 consecutive days. Area B was not observable in the field (no observable depression, standing water, or drowned out vegetation). Based on the lack of sufficient hydrology signatures in normal climatic years, plus additional soil information confirming the lack of hydric soil, no wetlands were identified within cropped portions of the site. al