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Amelia Ditch Study <br />August 10, 2023 <br />Page 2 <br /> <br />with minimal vegetation cover. Later historical aerials show little changes to the ditch besides <br />increased vegetation and development of I-35E and residential properties. <br />EXISTING CONDITIONS <br /> <br />The ditch to Lake Amelia serves a 255-acre drainage area, primarily consisting of agricultural and <br />lightly developed residential areas. See the Existing Conditions Map in Appendix A for these <br />drainage areas and Appendix B for modeled high water levels (HWLs) and peak flows. Table 1 <br />below and the Parcels Map of Appendix A summarize the properties that cover this study area. <br />Flows to the ditch originate in wetland complexes east of I-35E that collect runoff primarily from <br />grassed and forest cover, with some roadway and residential impervious cover. T hese basins <br />outlet via storm sewer running under I-35E to the two most upstream branches of the ditch. <br /> <br />Property Address Parcel ID(s) Property Owner Culvert <br />6518 20th Ave 253122310003 <br />253122320001 <br />253122330001 <br />Frances Burque A & B <br />1926 Birch St 263122410002 Farrell Properties LLC N/A <br />6483 20th Ave 263122440003 Judith Knabe D <br />6443 20th Ave 263122440005 Michael Kriegler N/A <br />6433 20th Ave 263122440004 Mathew and Mary <br />Vesel <br />E <br />1826 Birch St 263122430001 <br />353122120001 <br />James Cardinal <br />Andrew Cardinal Jr <br />F <br /> <br /> <br />The northern branch of the ditch is in an agricultural area, within drainage areas 3, 4, and 5. <br />There are two small basins on its upstream end that seem to empty in drier periods of the year. <br />Between these basins is Culvert A that appears to have filled with sediment and likely does not <br />provide any significant flows. The ditch section is less defined in this area, with widths varying <br />from 10-20 feet and depths typically around 1-3 feet. The channel is dry much of the year, only <br />seeing consistent water in the spring and around rainfall events. Outside of the channel is largely <br />flat, HWLs are very likely to spill out from the channel and into the s urrounding fields. <br /> <br />The southern branch of the ditch is also in an agricultural area, within drainage areas 7 and 8. <br />There is a small basin on its upstream end that seems to empty in drier periods of the year. <br />Culvert B runs below a driveway but similar to Culvert A, it appears to have filled with sediment <br />and likely does not provide any significant flows. The upstream ditch section is roughly 20 feet <br />wide and 2-3 feet deep. Downstream of the driveway crossing, the ditch section narrows to 10 -15 <br />feet wide and depths decrease to 1-2 feet. The channel is dry much of the year, only seeing <br />consistent water in the spring and around rainfall events. <br /> <br />These branches converge roughly 300 feet east of 20th Ave, still in an agricultural area. The ditch <br />section here is 20-25 feet wide and about 1 foot deep, with the exception of the pool just east of <br />20th Ave where the bottom is roughly 6 feet deep. There is a small channel running south to north <br />that also drains into the ditch. Besides the pool, the channel is dry much of the year, only seeing <br />consistent water in the spring and around rainfall events. The space outside the channel is largely <br />flat and there are known flooding concerns in the area. <br /> <br />The ditch crosses below 20th Ave via Culvert C, a 30” RCP. This culvert is well below much of the <br />surrounding ground elevations, but above the bottom elevations of the pools on either side.