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<br />SECTION VII
<br />
<br />Portions of the work which affect the Agricultural Ditch and
<br />Reservoir Company have been discussed with Mr. Leonard Rice,
<br />engineer for the company.
<br />The Colorado State Engineer's office has been contacted to dis-
<br />cuss its involvement in assuring correct construction of reservoirs
<br />and administration of existing reservoirs.
<br />
<br />DESIGN CRITERIA
<br />
<br />Design criteria was developed specifically for the Sanderson/
<br />Weir Gulch project taKing into consideration the peculiarities of
<br />the particular basins under study. The design criteria was not
<br />developed by Frasier & Gingery alone, but represents the input of
<br />local entities including the City and County of Denver Waste-
<br />water Control Division and Parks Department; City of Lakewood
<br />Department of Community Services, Parks and Recreation Depart-
<br />ment, and Community Development Department; Foothills Metropolitan
<br />Recreation and Park District, Agricultural Ditch and Reservoir
<br />Company; Urban Drainage and Flood Control District, and the
<br />basic parameters set forth in the Urban Storm Drainage Criteria
<br />Manual.
<br />
<br />The U. S. Army Corps of Engineers was contacted to discuss
<br />design criteria utilized in the hydrology and flood planning
<br />work accomplished on sections of weir Gulch, Sanderson Gulch,
<br />and North Sanderson Gulch. It was determined that the design
<br />approaches utilized on the gulches are similar in naturc,
<br />although specific information was not released by the Corps.
<br />
<br />SPECIAL CONSIDERATIONS
<br />
<br />COORDINATION WITH LOCAL ENTITIES, PARKS DEPARTMENTS, AND
<br />OTHER JURISDICTIONS
<br />
<br />The alternatives selected by the local entities and the urban
<br />Drainage and Flood Control District for detail~d investigation o~
<br />Phase B generally required that a 10 year des~gn storm be passea
<br />by any new facilities constructed on the gulches and that all
<br />areas subject to flooding from a 100 year storm occurrence be
<br />flood plain zoned. Thc City of Lakewood asked for 100 year cap-
<br />acity structure on certain major streets. To imple~nt this
<br />alternative, it is imperative that the system ~e des~gned such
<br />that it functions with little or nO damage dur~ng a 10 year storm
<br />runoff and will function with a reasonable amount af damage to
<br />the drainage system during a !l'.ajor storm OCC\lrr",nce such '"'s a lOO
<br />year. These constraints led to the basic ~pproach of designing
<br />structures to pass the 10 year flow with ponding depths at or be-
<br />low the street surface. During a 100 year storm occurrence local
<br />flooding would occur over the street surface at crossings and
<br />-o~:t:;J.ll~. ~c"\:;~- ..~ ..,,~ ~":;\""cl ""t\\'Q"n c!'ossings. This n"C',,'i'S'-
<br />~at~d instail;~i;~ ;f-d;~n~trea;-pr;t~ction On street overflow
<br />sections. Freeboard levels for the 10 year storm varied from
<br />o feet in extremely conjested areas to several feet in areas
<br />where adequate rights-of-way exists. In many areas, particularly
<br />on Sanderson Gulch, the 100 year storm runoff will be accommodated
<br />by the channel cross section with flooding occurring only at
<br />crossings, M~ch of weir Gulch and ~orth,Sanderson Gulch, how-
<br />ever, exhibits such restricted construct~on space that the channel
<br />is designed to carry only the 10 year storm. In t~ese cases, the
<br />".1."....1." ,,,,,ei yard" "Ul:~-QU"u.i.,,'l ~h", cl,ann",l "'~" rC'i"..rcd to p::::;::;
<br />the increment of flow between the 10 year and 100 year occurrence.
<br />
<br />Meetings were held during both Phase A and Phase B of the contract
<br />to discuss design approaches and criteria with representatives of
<br />involved organizations.
<br />
<br />Meetings wcre held with the City and County of Denver in which the
<br />Wastewater Control Division was represented by its Planning,
<br />Engineering, Administrative and Maintenance Sections. The first
<br />meetings reviewed the basic alternative approaches in a general
<br />context during Phase A, In Phase B additional mcetings were held
<br />in which specific design parameters were discussed inclucing channel
<br />cross sections, slope protection, drop structures, type of crossings,
<br />storaqe facilities, and maintenance aspects. The Denver Parks
<br />Oepartment was represented by Mr. Ed Johnson at one of the original
<br />criteria establishment meetings. It was felt that the input of
<br />the Parks Department and Maintenance Departments were of particular
<br />concern since they would be responsible for the long term function-
<br />ing of the project after construction.
<br />
<br />Meetings similar to those hcld with the City of Denver Were also
<br />held with the City of Lakewood to review both the original alter-
<br />native concepts and t~e Master Plan details. Although the majority
<br />of these meetings were directly with the Department of Community
<br />Servic",,<, t.h€ Pivl",ion "f community D€velapment and Parks Depart-
<br />ment were involved when felt necessary by the Department of
<br />Community Services,
<br />Discussions were held with the Foothills Metropolitan Recreation
<br />and pa:r:k District whero i~provement will be on facilities owned
<br />by the District. This applied to proposed improvements on the
<br />Green GabLes P"r'<. area and Kendrick Heservoir.
<br />
<br />SANDERSON GULCH THROUGH DENVER
<br />
<br />Lower Sanderson Gulch exhibits certain char~cteristics not found
<br />in any other portion of channels under consideration. Flood plain
<br />zoning of the area in the 19S0's largely excluded development from
<br />the imr.tediate vicinity of the ch:mnel. The existence of doveloped
<br />strip parks, or park land which has b~en purcha~ed Cl:lC r.ot developed,
<br />allows for extensive use of flood pla~ns w~th m~nor channel mod~f~-
<br />c~tions to assure the system will function during major storm
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