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II I I I I I I I I I I I I I I I I I I I stormwater management facilities, such as channels, detention ponds, and storm sewers, serve both a conveyance and storage function. When the space requirements associated with these facilities are considered, the provision for adequate drainage becomes a competing use for space along with other land uses. If adequate provision is not made in a land use plan for the drainage requirements, stormwater runoff shall conflict with other land uses and shall result in water damages, and shall impair or even disrupt the functioning of other urban systems. The City has participated in the development of regional basin- wide master plans to define the major drainageway facilities. These plans set forth requirements for new development and identify the required capital improvements. These master plans also provide criteria and requirements associated with unit runoff rates, level of affordable flood protection, etc. Where the criteria set forth in this manual conflict with the information in the master plan, the information in the master plan will govern. In addition, the ci ty requires that all new development and redevelopment shall participate in the design and construction of the major drainageway system within the development as defined by adopted master drainage plans or as required by the city. 1.4 Irrigation Facilities There are many irrigation ditches and reservoirs in the city area. The ditches and reservoirs have historically intercepted the storm runoff from the rural and agricultural type basins, generally without major problems. However, with urbanization of the basins, the storm runoff has increased in rate, quantity and frequency, and even the water quality has changed. In evaluating the interaction of irrigation ditches with a major drainageway for the purpose of basin delineation, the ditch should not be used as a basin boundary. Irrigation ditches are designed with flat slopes and limited carrying capacity, which decreases in the downstream direction. As a general rule, irrigation ditches cannot be used as an outfall point for the storm drainage system because of these physical limitations. In addition, certain ditches are abandoned after urbanization and, therefore, could not be considered a permanent part of the storm drainage system. Due to these changes in the urban stormwater response, irrigation facilities should not be considered as part of the available drainage system for new development. 1.5 Relationship to other Standards Whenever a provision of these Criteria, and any other provision in any law, ordinance, resolution, rule, or regulation of any kind, contain any restrictions covering any of the same subject matter, the most restrictive standard shall apply. 1 - 3