Laserfiche WebLink
<br /> <br />Mim F,~- ~ and Fmvaommtsl 303-469-1076 <br />ox <br />There have been recent concerns about the availability of the Hazel A storage due to groundwater <br />infiltration . To address this, the storage capacity of the pond without the decant system end <br />without the storage behind the bulkhead was analyzed. C~urently there is an additional 0.76 <br />aae-feet of storage above the ice to the low point of the pond embanlmtent (assuming the decant <br />system is closed). I calculated the stormwater runoff into the pond from the 10-year, 24 hour <br />stone to be 0.275 aae-fcet. Thus, the total nmoff to the pond from back-to-back 100.year and <br />10.year stones is 0.724 acre-feet The incremental capacity now available in the pond of 0.76 <br />aae-feet can contain these back-to-back storms. If the dry capacity of the pond of 0.88 aae-fcet <br />is considered, the surplus capacity for these two storms is more thmr 20%. <br />Your June 25 adequacy letter suggested a design standard for the permanently raised pond of <br />40°,io of the 100-year, 24-hour event plus the full 100.year 9nd 14•yeer stomps. This would add <br />0.18 acre-fcet to the 0.724 aae-feet, for a total of 0.904 aae-feet runoff to the pond from these <br />three storms back-to-baclc This slightly exceeds the etarent dry opacity of the pond of 0.88 aae <br />feet. <br />~! lar:atlo n :. <br />Abova~icr .9~utn~: V oiutn•': <br />~~~~~Aere~Ft:~.::~: ::~:~::::~:::':~:':~.': ~':':t:i:'::~::~::~ <br />~~ :~:~~~CemmenYr~~~~~~~ <br /> <br />0.0 <br /> <br />0.7 0.021 <br /> <br />0.2 0.053 <br /> <br />3 .099 <br /> <br />0.4 0.133 <br /> <br />0.5 0.174 <br /> <br />0.8 0.215 <br /> <br />0.7 0.259 <br /> <br />o.e o.3ot <br /> <br />0.9 0.345 <br /> <br />1.'v 0.309 <br /> <br />1.1 0.43! <br /> <br />1.2 0.478 <br /> <br />7.3 0.524 Riser Inlet HMI ht <br /> <br />1.4 0.570 <br /> <br />1.5 0.817 <br /> <br />1 .8 0.884 <br /> <br /> <br /> <br />1.8 0.758 To of Embsnkm•nt <br />