Laserfiche WebLink
' ~~bering, ~1~urth & Associates <br />' Consulting Civil Engineers <br />Registered Land Surveyors <br />1015 Elkton Drive • Colorado Springs, Colorado 80907 • Phone (719) 531-6200 • Faz (719) 531-6266 Ext. 3 <br />1 <br />MEMO: Final Design Analysis for <br />' HR-6 Snyder Quarry CAP <br />February 6, 1990 <br />Protect No. 89002.003 <br />1 <br />' OVERVIER'- <br /> This memo is a summary of a final design analysis that has been done by <br /> Obering, Wurth &, Associates (OWA) !n response to the MLRD's <br />' recommendations relative to the HR-6 culvert crossing !n the CAP f~~r the <br /> Snyder Quarry Access Road. The intent is to present alternates for all parties <br /> to consider prior to a response to MLRD and construction. <br />' The Black Canyon Master Drainage Report and Plan prepared by Weiss <br /> Consulting Engineers, Inc. dated January, 1980 identified a drainage Subba.sin I- <br />' 1 which is the subJect area oP this detailed analysis. The Snyder 6luarry <br />Access Road Corrective Action Plan (CAP) prepared by Obering, Wurth & <br /> Associates (OWA) dated October, 1989 further ldentlfied two subbasins HR-6 <br /> and HR-7_wlthln the originally master-planned I-1 Subbasln. (See attached <br />' Exhibit A -Sheet 1 of 1 -Area Drainage Plan). <br /> The Subbasln HR-6 outfalls Lnto an existing natural drainage course whtch <br /> crosses both the Snyder Quarry Access Road and Cedar Heights Drive. The <br /> Weiss Master Plan called fora 24" culvert (ldentlfied on attached Exhlblt B as <br /> Proposed Culvert A) across Cedar Heights Drive and, although It w:is not <br /> shown on the map, implied a similar or other crossing at the Snyder `luarry <br />' Access Road. Subbasln HR-7 consists of the contributing drainage area to an <br /> exlsting natural drainage course which outfalls into an existing b4"/30" <br /> drainage facility located near the Cedar Heights guard house. <br />' In 1980, at the time of preparation of the Master Plan, facility design for <br /> the Qe storm event was required. The criteria at the time of preparation of <br /> the Master Plan was different from the current criteria (revised O~:tober <br />' 1987). Flows are approximately 3091 higher as a result of the new criteria <br /> being applied to the same basins. <br />' A subdivision Drainage Report and Plan was prepared for Cedar Heights <br />Filing No. 1 by Weiss Consulting Engineers, Inc. dated July 1980. I.n this <br />report, the master-planned Basin I-1 was divided Into Subbaslns I-l.a., I-l.b. <br />' and I-l.c. (see attached Exhibit B). The "Proposed Culvert A" under Cedar <br />Heights Drive was shown relocated approximately 400 feet South ~~f the <br />exlsting natural drainage course (the recommended size did not change). A <br />' culvert was still not shown under the Snyder Quarry Access Road i.n the <br />existing natural drainage course. The portion of the master-planned I.1. bas[n <br />1 <br /> <br />