North Peoria Area Drainage Master Plan - Flood Control District of ...

minimize the effect of urbanization on stormwaterrunoff and conveyance while recognizingthe values of the community and theopportunity to protect the unique characteristicsof the region. A holistic approach insuresthat public’s safety and quality of life is maintained.Goals of the North Peoria ADMP are:• Identify flood and erosion hazards alongmajor watercourses.• Develop policies and strategies to protectresidents from flood and erosion hazards.• Preserve the natural flood control functionof the existing washes and channels.• Incorporate public and private interests,issues, and concerns.• Minimize future expenditures of publicfunds for flood control and emergencymanagement.• Consider environmental and landscapecharacteristics of the watershed in thedevelopment of watershed managementalternatives.• Minimize disturbance of existing floodplainand floodway ecosystem and habitats.• Consider multiple-use activities for floodplainareas.BACKGROUNDPROJECT AREAThe North Peoria ADMP study area encompassesapproximately 73 square miles withinunincorporated Maricopa County and theCity of Peoria. The study area is divided intofour planning areas based on physical characteristicsand/or geographic location of eachplanning area. The four planning areas are theMorgan City Area, Big Spring Area, East TerraceArea, and the Twin Buttes Area. TheHieroglyphic Mountains, located within theMorgan City Area, Big Spring Area, and thenorthern portion of the Twin Buttes Area arecharacterized by peak, ridge, wash, and valleylandforms. Terrain slopes within the HieroglyphicMountains range from less than 10percent to greater than 25 percent. Rock outcropand rock fragments typify soil constituentswithin the Hieroglyphic Mountains.Within the Morgan City Area and Big SpringArea, washes are typically incised in rock orwell-cemented alluvial material. The East Terracearea located east of the Agua Fria Riverand the southern portion of the Twin ButtesArea have landforms characterized with terrainslopes of less than 10 percent and areunderlain typically by alluvial material. Sinuousnatural channels that are cut into alluvialmaterial characterize washes in the East TerraceArea and in the southern portion of theTwin Buttes Area. With the exception of thelower reach of Morgan City Wash, washesdraining the study area watersheds areephemeral. Springs deliver water to the lowerreach of Morgan City Wash providing flowyear around. Figure 2 displays major watercoursesthat drain from the study area to theAgua Fria River, specific planning areas delineatedby unique physical characteristics, andphotographs of some of the physical characteristicof the area.One of the unique characteristics of the area isthe contrast in terrain from the planes and flatlands of the valley to the varied landforms ofthe Hieroglyphic Mountains. Figure 3, TerrainSlope Map, is a graphic representation ofterrain slope in the area. Terrain slope is oftenused by communities and agencies to definesignificant areas of preservation or areaswhere special development considerationsmust be met. Maricopa County encouragespreservation of, and applies development considerationsfor significant mountainous areaswith terrain slopes of greater than 15 percentwhere as the City of Peoria applies specialdevelopment considerations for areas withterrain slopes of greater than 10 percent.3