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May 16, 1957 - Boulder Daily Camera: Nederland reservoir of the Public Service Company is now half full, The Camera was informed today. Rumor had it that water was spilling over the dam for the first time in many years. Prospects are good for the reservoir filling but not until later in the summer. Meantime reservoirs in Boulder Valley are rapid filling with flood water, and irrigation ditches (not those running through Boulder) are carrying a full load to the reservoirs they service. 2.4 Flood Protection Measures There were no structural flood protection measures at the time of the initial study in Boulder County. Presently, Barker Reservoir on Boulder Creek and Gross Reservoir on South Boulder Creek are far enough upstream from the areas studied by detailed methods that their flood protection effects are negligible. Since 1971, Boulder County has undertaken an active program of floodplain management. Past urbanization in the City of Boulder has encroached drainageways and reduced stream storage, thereby increasing runoff peaks and volumes. Undersized culverts and channels exist throughout the city. A few measures have been taken to alleviate these problems on some of the study streams and are discussed below. This discussion excludes drainage improvements constructed to provide protection from erosion. The degree to which the flood-control measures discussed protect fram return interval floods is unknown at this time. Flood-protection measures along Wonderland Creek consist of Wonderland Lake (Reference 21); the ponding area between Wonderland Lake and Broadway; the channelization projects along the Winding Trail Village and Aspen Grove developments, located between the Longment Diagonal and 26th Street (Reference 22); the recently constructed 26 Avenue Crossing culvert and drop inlet (Reference 22); and the detention pond east of 47th Street (Reference 23). Wonderland Lake, while not designed to provide flood protection, will attenuate the 100-year peak floodflow fram 400 to 100 cfs. For the routing analysis, Wonderland Lake will be considered filled to the spillway crest at the time of sto~ runoff routing. The area between Wonderland Lake and Broadway creates an unplanned flood-control structure, because the culvert at Broadway will convey very little flow and a considerable ponding volume is available. This unplanned flood reservoir was not included in the hydrologic analysis. Diversion flow from Fou~le Canyon Creek to the north will also reach Wonderland Creek at this location. 30