2023-07-12_PERMIT FILE - M2022048 (2)

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In the future (>10 years), L.G. Everist may propose aggregate extraction at West Farm, as economic aggregate reserves are present in both the primary and alluvial terraces. This jurisdictional determination request will assist L.G. Everist in further managing the property through reconstructing the agricultural irrigation distribution and tailwater collection system for more efficient agricultural production,while avoiding and minimizing impacts to waters of the United States (including jurisdictional wetlands). West Farm Surface Water Features Man-made and natural surface water features are depicted on the appended Figure 1 (L.G. Everist West Farm Surface Water Features). A description of the surface water features is contained in Table 1. (L.G. Everist West Farm Surface Hydrologic Features). The following text contains further descriptions of the features to assist the Corps in determining the jurisdictional nature of each. Descriptions will follow the alpha-numeric designations of the above figure and table. Al. This feature is a man-made tailwater collection ditch that collects irrigation water runoff from the field to the north and terminates at a tailwater sump (A2) on the southeast edge of the secondary alluvial terrace. A2. This feature in a constructed tailwater sump (Figure 2) that collects water from the tailwater collection ditch to the west (Al). Water within A2 ultimately decants through a culvert to the primary alluvial terrace below, where tailwater enters surface water feature B4 and ultimately enters the South Platte River to the north. B1. This drain is a constructed ditch that originates at the irrigation pivot pump in the southeast corner of the property. Water from the installed pivot pump flows into this feature and ultimately to the irrigation tailwater pond(132). Water may also enter this feature from the off-site irrigation pond(D 1)through irrigation ditch D2. Ultimately,water from B 1 can be used for flood irrigation (pumped from 132) or discharged into the tailwater ditch B3, which ultimately discharges into the South Platte River to the north. B2. B2 is a man-made irrigation tailwater collection pond, situated downgradient from the irrigation pivot pump (173) and the irrigation water drain (B 1). Based on the 1978 USGS topographic map, this feature, while anthropogenic, was likely constructed in a natural alluvial terrace channel(depicted as a blue line on the 1978 topography). The origin of this natural drainage feature is to the south of West Farm,though no water source is identifiable on the topographic map. Currently, water flowage into B2 (and B 1) is from the irrigation pivot pump (F3) and/or the off-site irrigation pond (D1) on the adjacent farm to the south of West Farm. B3. This feature is currently a tailwater collection ditch, originating at B2, traversing the south parcel of West Farm to the north,crossing under Weld County Road 32.5,and entering the surface drainage B4 within the north parcel (Figure 3). The current alignment of B3 reveals that it is man-made,aligned along the east boundary of an irrigated agricultural field. The 1978 topographic map depicts the blue line drainage in the general vicinity of the current B3,however,this surface drainage is no longer present on the site. It was concluded L.G.Everist West Farm Jurisdictional Determination Request Page 5 of 14