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ORAf1 SECTXOR XV - XDENTXFICATIOR OF DRAINAGE PROBLEMS A variety of drainage problems exist throughout the MPA. In general, they can be classified into three categories: major drainageway flooding, local drainage problems and nuisance drainage. Major drainage flooding involved potential flooding on the Blue River and its major tributaries studied by FEMA as well as the larger local drainageways including the Klack, Jones Gulch, and Lomax Gulch. The local drainage problems generally involve inadequate capacity of the culvert system that conveys flows to the major drainage system. Nuisance type drainage problems involve improper grading of lots, ponding areas in streets, small areas of ice buildup, and other problems which are localized and cause mostly inconvenience with minimal damage. This study addresses only the former two types of problems, major drainageway flooding and local drainage problems. Nuisance drainage problems are beyond the level of detail of this report. These types of problems are best addressed while studying an area in detail such as when a street project is being designed or when the situation is requiring continuous maintenance. MAJOR DRAINAGEWAY PROBLEM AREAS The streams considered under the major drainageway category include the Blue River, Lehman Gulch, Sawmill Gulch, Cucumber Gulch, south Barton Gulch, Middle Barton Gulch, North Barton Gulch, Gold Run Gulch, French Creek and Illinois Gulch. Flooding problems on the Blue River, Sawmill Gulch French Creek, and Illinois GUlch were discussed in detail in SECT lOR 111 and will be summarized in this section. Lehman Gulch was included in the FEMA detail~d mapping. since there is no development other than a ski run, along this stream, flooding problems do not exist. The other drainages have not had additional flood mapping performed, however, their peak discharges have been estimated and based on the estimated discharges. There are some obvious flooding problems. Summary of Blue River, French Creek, Sawmill Gulch and Illinois Gulch Flooding The Blue River has only three areas of significant concern, these are the two Broken Lance Drive crossings and the low lying area just upstream of the Washington Avenue bridge on the south side of the stream. The latter problem, could be readily solved by additional fill material to raise the overbank area where the flow may break out. The lower Broken Lance Drive crossing would require installation of larger culverts or a box culvert. The upper Broken Lance Orive flooding could be eliminated by regrading the area along the roadway, upstream of the bridge. Also of concern on the Blue River are two headwalls where scour downstream of the culverts 41