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I I I I I I I I I I I I I I I I I I I 51 The constraints included the need for control 1 ing the flooding which would have a one percent chance of occurring In any given year, use of the multi-purpose -- multi-use concept fully to create as many auxili- ary urban benefits as is reasonable, the importance of maintaining and improving the streamside amenities, the fact that the City and County must not be subjected to undue legal 1 iability as a result of flooding, and in general the importance of improving the urban environment which must be stressed in all phases of the work. During the course of the Master Plan preparation, numerous conflicts arose. A prime example is the treatment of the Bear Canyon Creek channel problem between the NCAR property and Table Me?a Drive. It was here that every effort was made to plan for leaving the stream in its natural COn- dition and util izlng flood plain zoning to accompl ish the needed objec- tives. It was decided to show channel ization in this reach because of the concern for excessive spreading of flood waters and degradation of the alluvial fan. However, it is noted on the drawing that the flood plain alternate still exists. It would be practical if further studies showed that the erosion problem could be overcome and if it was found esthetically acceptable to construct small rubble and mortar retaining walls at selected locations to contain the flooding within reasonable 1 imits. The extent of the proJect calls for policy decisions in regard to the setting of prIorities and perhaps even modification of the plan if de- sired by the citizens. For instance, on Bear Canyon Creek it would not be out of the question to plan for a lower degree of flood protection or to put Bear Canyon Creek lower on the priority list, using the Master Plan in the mean time as a guide for reservIng of right-of-way, con- struction of proper sized bridges and culverts as streets and thorough- fares are built, and construction of portions of the channel as the need for borrow material arIses from time to time. In essence, the Master Plan was prepared with a strong attempt at fully relating to the other urban subsystems such as traffic, green- belts, open space, sewer and water utilities, and hiking and bicycle paths to encourage less dependence upon the automobile. An example of this has been a minimum six-foot clearance in culverts to permit pedes- trians to cross under maJor thoroughfares. Of the numerous alternates which were considered, and this Included the poss Ib i llty of a "deep tunnel plan" such as may be pract leal for Boulder Creek from the canyon mouth to east of 30th Street, the Master Plan as presented in this two-volume report represents the best layout for maximum benefIts with the lowest reasonable cost fItting the goals and obJectives establIshed within the framework of the Drainaqe Manual.