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8. Plcase provide engineering designs and supporting calculations for the sizing of <br />spillways, culverts, and%or any other hydraulic stntcture that will be inslallcd in the <br />reclaimed pond. Please note that any permanent hydraulic feature will need to he <br />adryuatrly sired to withstand the velocity and volume of Ilows expected Isom a 101)-year <br />tl+x~d event. (Wr suggest you rrfrr to the attached copy ul the Division's "In-stream <br />Aggregate Extraction & Rechunation Guidance Document" that provides specific design <br />criteria fi>r siring of hydraulic structures(. Plcase provide. FULLY' :11)DRF.SSI?D <br />9. Plcase yuantil'y the velocity and volume of slows expected on site from a 100-ticar Il+x~d <br />event, as well as the elevation of the I(10-near base flood event and its relation to the <br />elevation of the spillways and lake shore embankment. Also, please yuantil'y or <br />characterize the expected groundwater surface between the stream channel and the <br />adjacent Iloodplain to the north under such an event. Plcase provide. FULLY <br />ADDRESSED <br />10. Plcase quantify the cclocity and volume of flow expected as well as magnitude of flood <br />event rryuirrd to produce a "banktirll" event in the adjacent reach oP the St. Vrain River. <br />:Vso. please quantify ur dutracterire the exprctrd groundw•atrr surface between the stream <br />channel and the adjacent tloodplain to the north under such an event. Plcase provide. <br />FU1.L.Y' ADDRFitiSED <br />I L Plrter clarify the cnlcna the applicant used to detcnninc thr number ul spillways to <br />install m the reclaimed lake. Since dte reclaimed lake and slurry wall installation will he <br />adjacent to a reach of the St. Vrain River that is over 1 mile in length, the applicant will <br />need to quantify Utc number of spillways needed and the spacing inter al nc~edcd to rnsurc <br />that Iloodwatets from a l0U-year Ilood event will be discharged back safely to the main <br />ch;uutel nl' thr St. Vrain Ricer within a reasonable period of time and also maintain the <br />stnrrurral integrity of the slum• wall installation as well as the surrounding area. Please <br />provide. ADDI'flO\r\L IM1FUIZM:\flOv REQUIRED - SEF. Sf_('OND ADI~.QL;ACY <br />REVIEW ITEM ro4 IV MEMU FROM I Obi S('lIR1iINI:R <br />12. Rcciew• of the Reclamation Plan Maps provided indicates that the lake edge ranges <br />from 100-3(10 feet them the north hank of the St. Vrain River. The exact location of the <br />slurry wall hchvicen the lake edge and north bank of the river is unknown. Plcase provide a <br />s[nunrral anah•sis th:u vrrilies the minimum width or bulTcr of soil needed on either side <br />of the slurry wall ti+ prucidr adequate support during saturated soil conditions, a_c well :mac <br />wuierarapiddrtwdownscrnario. Plcase provide. PULLY':\DDRIiSSED <br />6.J.7 F.\Illttll G - ~~atcr Information <br />13. In ronlormancr with Rulc 3. L6(i ), please eerily whcthrr there are any registered wells <br />+cithin six hundred (r>ti0) feet of the proposed slurry wall installation. If yes, please <br />pruvidr a map rxhihit +ahich shows the location and descnbrs Ihr ownership of rack <br />registered well. (Wells registered with the ORice of the Siate Enginrerl. Plcase respond. <br />FULLY ADURESSI{D <br />