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• III IIIIIIIIIIIII III • HOWE PIT-BULL SEEP RELOCATION (Chronology of Events) Permit No. M-78.052 1. Division of Minerals & Geology was invited by Urban Drainage & Flood Control District (UDFCD) [o participate in a meeting on June 13, 2001 regarding emergency flood control measures [hat were implemented by UDFCD in May, 2001 at the Howe Pit, Permit No. M-78-052. The Howe Pit is a lazge alluvial sand & gravel operation located immediately east of the South Platte River between Easl 104`" Avenue and Easl 120'" Avenue. The Howe Pit is operated by Mobile Pxemix Concrete, lnc. 2. A[ [he June 13, 2001 meeting the Division learned that on May 5, 2001 the flood control levee in the northwest corner of MPM's operation breached and a significant portion of [he South Platte River flow crossed over into [he Howe Pit in an area that is known as [he Bull Seep Slough. The breach and resulting emergency flood control measures by UDFCD are alleged to be a dvect result of the manner in which the Bull Seep drainage channel was relocated by the operator and tied into [he pre-existing Bull Seep Slough. 3. The Division has confirmed that the area of the breach and a portion of the Bull Seep Slough occur within the permit boundary of the Howe Pit. Flows from the May 5, 2001 event continued through [he Bull Seep Slough and discharged into the South Platte River. The volume of flow recorded on May 5, 2001 at 7 PM at the nearby Henderson gauge was 5520 cfs. 4. Afield inspection conducted by the Division July 5, 2001 noted [he following based on a number of measurements taken: a. There are 2101ineaz feet of flood control levee repair implemented by UDFCD in May, 2001. b. The relocated Bull Seep at and near the location where the Flood control levee was repaired by UDFCD is 60 feet from the South Platte River, (from SPR water's edge to Bull Seep water's edge at toe of flood control levee) c. There are a number of areas of significant bank erosion within the Bull Seep Slough area. d. There is a 2"d area of instability of the relocated Bull Seep located S 101inear fee[ south of [he southern end of the flood control levee repair. This area is also 60 feet from the South Platte River (based on maps provided by UDFCD). 5. Based on the maps and permit correspondence associated with the 1990 permit amendment, the Bull Seep is [o be relocated at least 200 feet from [he South Platte River. (See Amended Drainage Plan; Exhibits G-1 & G-2; Review Comments from UDFCD dated 6/15/90, 8/14/90; DMG adequacy review comments dated 7/27/90, 7/25/90; the operator's adequacy response dated 8/10/90, 9/7/90, 9/10/90; and the Tuttle Applegate letter [o John Hickman of Mobile Premix dated 8/3/90). 6. Review of survey maps of [he Bull Seep relocation provided by UDFCD indicate that [here are a[ least 550 lineaz feet of relocated Bull Seep that are less than 200 feet from the South Platte River. Of these 550 linear feet, approximately 300 linear feet of the Bull Seep were relocated immediately adjacent to or at the toe of the pre-existing Flood control levee, and only 60 feet from the edge of the South Platte River. Aerial photographs of [he Howe Pi[ indicate the Bull Seep relocation was untimely and not in accordance with [he time schedule provided in the 1990 amendment application. Review of the approved 1990 Amendment Application indicates "Bull Seep relocation -constructed prior [o mining in Stage 4 and prior [o excavation in Stage 4 the Bull Seep will be routed around the south and west areas of [he property." An aerial photograph of the Howe Pit taken on 7/7/95 shows [hat [here was excavation in [he Stage 4 Area, but the Bull Seep remained in its original location. An aerial photograph of the Howe Pit taken on 10/9/96 indicates that the Bull Seep had been relocated to the west of the Stage 4 area. These photographs verify that the relocation of the Bull Seep was untimely and not in accordance with the approved plan.