North Peoria Area Drainage Master Plan - Flood Control District of ...
North Peoria Area Drainage Master Plan - Flood Control District of ... North Peoria Area Drainage Master Plan - Flood Control District of ...
developed for the Estrella Roadway, whichwill cross the alignment of 115th Avenue, andTwin Buttes Wash approximately 1000 feetdownstream of the subject structure, howeverthere are no improvements proposed thatwould mitigate flooding to the structure or tothe alignment of 115th Avenue.OPTIONSUnder current Maricopa County floodplainregulations the existing structure could not berebuilt if, due to flooding, fire, or some othercatastrophic event, the structure suffereddamages of greater than 50 percent of itsappraised value. In addition, the current orfuture owners could not obtain building permitsfor new structures. A possible option toaddress the problem is to recommend theproperty be considered for a voluntary acquisitionor on-site relocation program managedby the District. If the home qualifies for theprogram, the homeowner would have theoption of selling their parcel to the Districtand having the structure removed from thesite so that the land could return to its naturalor near natural state or, if there are areas of theparcel outside the floodway and erosion hazardzone, and the homeowner wishes to movetheir home, the homeowner would have theoption of relocating the residence on-site, butoutside the high hazard areas.41
NORTH PEORIAAREA DRAINAGE MASTER PLANGLOSSARY100-year stormA rainfall event that has a 1% chance of occurringor being exceeded in any given year.aggradationA rise in the channel bottom elevation due toan accumulation of sediment over time.avulsionAn avulsion occurs when a watercourse channelmigrates laterally to another positionwithin the natural floodplain. Lateral channelmigration and head cutting are contributingelements to the avulsion process.braidedA braided watercourse is one flowing in severaldividing and reuniting channels resemblingthe stands of a braid. Avulsion andlateral migration processes contribute to thedevelopment of a braided watercourse.erosionThe group of processes whereby rock and/orsediment deposits are loosened and/or dissolvedand removed from their original locations.existing conditionsPhysical conditions within a watershed orwatercourse at the time of evaluation.100-year floodplainA special flood hazard zone that is defined bythe area along a wash that gets wet and carrieswater during a 100-year flood. Criterion todefine the 100-year floodplain is establishedby the FEMA.floodwayThe floodway is that portion of the floodplainreserved by FEMA for the conveyance offloodwaters during a 100-year flood. Buildingsand/or structures that would obstructflow are not allowed within the floodwayboundaries.channelThe deepest portion of a watercourse throughwhich the majority of runoff is conveyed.Braided watercourses will have multiplechannels.computer modelsComputer models developed as part of thisstudy are developed to model hydrologic andhydraulic conditions. The models simulate astorm event (such as the 100-year storm) andestimates how much runoff will be generatedfrom a given area (hydrology) and how deepand fast the runoff will move (hydraulics)within a watercourse draining the given area.degradationA deepening of a channel over time or in a singlestorm event due to erosion processes.ephemeral watercourseA watercourse or potion of a watercourse thatflows only in direct response to rainfall.floodway fringeThe floodway fringe is the portion of the 100-year floodplain located adjacent too and outsideof the FEMA 100-year floodway. UnderFEMA regulations development within thefloodway fringe is permissible providing certaincriteria are met.floodplain encroachmentFloodplain encroachment is defined by developmentactivity that occurs within the floodwayfringe. The collective impact of thedevelopment activity can not increase the 100-year water surface elevation over FEMA 100-year floodway water surface elevations.Floodway water surface elevations are up toone foot higher than floodplain elevations.future conditionsFor this study future condition is the proposedphysical condition of the watershed based onthe City of Peoria’s General Plan.42
- Page 2 and 3: TABLE OF CONTENTSPreface ..........
- Page 4: PREFACEAt the request of the City o
- Page 8 and 9: LIST OF TABLESTable 1: Regional and
- Page 10 and 11: INTRODUCTIONThe natural physical ch
- Page 12 and 13: minimize the effect of urbanization
- Page 14 and 15: Peoria General PlanThe Peoria Gener
- Page 16 and 17: HYDRAULICS8QQDPHG:DVK%LJ6SULQJHydra
- Page 18 and 19: FLOOD AND EROSION HAZARD ZONESWith
- Page 20 and 21: ing them before they are destroyed
- Page 22 and 23: PUBLIC INVOLVEMENTAn integral part
- Page 24 and 25: hard pan, typically less than two f
- Page 26 and 27: Economic CriterionThe evaluation of
- Page 28 and 29: Table 4Summary of Evaluation Result
- Page 30 and 31: INTRODUCTIONRULES OF DEVELOPMENTCom
- Page 32 and 33: Objective EH1.3Identify erosion haz
- Page 34 and 35: the purpose of watershed and waterc
- Page 36 and 37: the North Peoria ADMP. Users of the
- Page 38 and 39: (short, constricted reaches), backw
- Page 40 and 41: • Collect hydrologic data - peak
- Page 42 and 43: • Basin Outlet (Culvert). The bas
- Page 44 and 45: Low Impact Structural AlternativeFo
- Page 46 and 47: ack at the natural channel bed. In
- Page 48 and 49: stability, and to assure structure
- Page 52 and 53: gabion mattressA gabion mattress is
- Page 54 and 55: Maricopa County, August 21, 1993, H
- Page 70 and 71: 100-year W.S. ElevationBufferFEMA 1
- Page 72 and 73: NORTH PEORIA AREA DRAINAGE MASTER P
- Page 74: 100-year W.S. ElevationFEMA 100-yea
NORTH PEORIAAREA DRAINAGE MASTER PLANGLOSSARY100-year stormA rainfall event that has a 1% chance <strong>of</strong> occurringor being exceeded in any given year.aggradationA rise in the channel bottom elevation due toan accumulation <strong>of</strong> sediment over time.avulsionAn avulsion occurs when a watercourse channelmigrates laterally to another positionwithin the natural floodplain. Lateral channelmigration and head cutting are contributingelements to the avulsion process.braidedA braided watercourse is one flowing in severaldividing and reuniting channels resemblingthe stands <strong>of</strong> a braid. Avulsion andlateral migration processes contribute to thedevelopment <strong>of</strong> a braided watercourse.erosionThe group <strong>of</strong> processes whereby rock and/orsediment deposits are loosened and/or dissolvedand removed from their original locations.existing conditionsPhysical conditions within a watershed orwatercourse at the time <strong>of</strong> evaluation.100-year floodplainA special flood hazard zone that is defined bythe area along a wash that gets wet and carrieswater during a 100-year flood. Criterion todefine the 100-year floodplain is establishedby the FEMA.floodwayThe floodway is that portion <strong>of</strong> the floodplainreserved by FEMA for the conveyance <strong>of</strong>floodwaters during a 100-year flood. Buildingsand/or structures that would obstructflow are not allowed within the floodwayboundaries.channelThe deepest portion <strong>of</strong> a watercourse throughwhich the majority <strong>of</strong> run<strong>of</strong>f is conveyed.Braided watercourses will have multiplechannels.computer modelsComputer models developed as part <strong>of</strong> thisstudy are developed to model hydrologic andhydraulic conditions. The models simulate astorm event (such as the 100-year storm) andestimates how much run<strong>of</strong>f will be generatedfrom a given area (hydrology) and how deepand fast the run<strong>of</strong>f will move (hydraulics)within a watercourse draining the given area.degradationA deepening <strong>of</strong> a channel over time or in a singlestorm event due to erosion processes.ephemeral watercourseA watercourse or potion <strong>of</strong> a watercourse thatflows only in direct response to rainfall.floodway fringeThe floodway fringe is the portion <strong>of</strong> the 100-year floodplain located adjacent too and outside<strong>of</strong> the FEMA 100-year floodway. UnderFEMA regulations development within thefloodway fringe is permissible providing certaincriteria are met.floodplain encroachment<strong>Flood</strong>plain encroachment is defined by developmentactivity that occurs within the floodwayfringe. The collective impact <strong>of</strong> thedevelopment activity can not increase the 100-year water surface elevation over FEMA 100-year floodway water surface elevations.<strong>Flood</strong>way water surface elevations are up toone foot higher than floodplain elevations.future conditionsFor this study future condition is the proposedphysical condition <strong>of</strong> the watershed based onthe City <strong>of</strong> <strong>Peoria</strong>’s General <strong>Plan</strong>.42
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