Post on 20-Jan-2016
VILLAGE OF PATCH, NM, FEASIBILITY STUDY
Village of Patch
Case Study
Seattle Environmental Planning
ClassJune, 2009
US Army Corps of EngineersAlbuquerque District
1HO #s 2 & 2aCh 1 Module 2
Patch,
Study Authority
Authority
“ The Secretary of the Army is hereby authorized directed to cause surveys for flood control and allied purposes, including channel and major drainage improvements to be made under the direction of the Chief of Engineers, in drainage areas of the United States and its territorial possessions, which include the localities specifically named in this section”…Patch, NM
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VILLAGE OF PATCH, NM, FEASIBILITY STUDY
US Army Corps of EngineersAlbuquerque District
The study is located in Patch, NM. The purpose of the feasibility study is to determine Federal interest and optimize a flood damage reduction/ecosystem restoration plan for the city of Patch. Structures and roadways have been impacted by flows from the surrounding mountains, significantly flooding the community twice in the last 15 years. Flooding originates from two sources-Spring Canyon and Placitas Arroyo. Initial investigations determined that there is a likely Federal interest in constructing flood control projects in the area, the most probable alternatives being a small dam at Spring Canyon. Repeated flooding limits fishery populations.
Regional Setting
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Drainage Area
VILLAGE OF PATCH, NM, FEASIBILITY STUDY
US Army Corps of EngineersAlbuquerque District
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Patch, New Mexico
Floodplains
VILLAGE OF PATCH, NM, FEASIBILITY STUDY
US Army Corps of EngineersAlbuquerque District
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Patch
Flood History:
• The Village of Patch experienced significant Flood events in 1988, 2002 and 2006.
• FEMA and Corps’ analyses determined Spring Canyon is a flood threat to the Village of Hatch.
•The entire Village of Patch lies within a 100-year Floodplain
VILLAGE OF PATCH, NM, FEASIBILITY STUDY
US Army Corps of EngineersAlbuquerque District
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Flood Potential:
• Spring Canyon channel capacity is 1,300 CFX (100-year flow is-1% chance event-estimated at 2,600 CFS)
• Estimated average annualized flood damages of $10.1 million from Spring Canyon
VILLAGE OF PATCH, NM, FEASIBILITY STUDY
US Army Corps of EngineersAlbuquerque District
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Existing and Likely Future Without-Project Conditions
• Physical Setting
17.2 square mile watershed draining from the south flowing north into the Rio Grande
An upstream detention structure controls 15.4 square miles of the basin
Elevation in the drainage drops from 6,000 ft to 4,030 ft
Flooding events in 1988, 1992 and 2006 left three feet of water in the street
VILLAGE OF PATCH, NM, FEASIBILITY STUDY
US Army Corps of EngineersAlbuquerque District
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Existing and Likely Future Without-Project Conditions
• Physical Setting (continued)
Once flows enter the village there is no clear drainage pathway into the Rio Grande; floodwaters remain in place until evaporated.
The Village storm drainage system is sized for a 5-year event. Sediment renders the system largely inoperable during larger events
VILLAGE OF PATCH, NM, FEASIBILITY STUDY
US Army Corps of EngineersAlbuquerque District
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Existing and Likely Future Without-Project Conditions
•Social and Economic Conditions
2004 population of 10,661
1284 single residential structures within the 1% event floodplain
187 commercial structures within the 1% event floodplain
127 public structures within the 1% event floodplain
10 apartment within the 1% event floodplain
VILLAGE OF PATCH, NM, FEASIBILITY STUDY
US Army Corps of EngineersAlbuquerque District
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Existing and Likely Future Without-Project Conditions
• Social and Economic Conditions (continued)
Median income for a household: $21,200
Many seasonal inhabitants
“Chile capitol of the world”
172 homes with flood insurance
VILLAGE OF PATCH, NM, FEASIBILITY STUDY
US Army Corps of EngineersAlbuquerque District
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More Information• Non-damaging Channel Capacity
• 10,300 cubic feet per second (cfs)
• 100-year flow
20,600 cfs
• Flood Damages
Estimated average annualized flood damages $10.1 Mil
Federal Disaster Area in 2006
VILLAGE OF PATCH, NM, FEASIBILITY STUDY
US Army Corps of EngineersAlbuquerque District
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More Information• Biological Communities
Southern cottonwood-willow riparian forest occurs in Spring Creek Watershed. Salt Cedar dominates Placitas Arroyo. The forest provides canopy cover needed for sensitive nesting birds.
VILLAGE OF PATCH, NM, FEASIBILITY STUDY
US Army Corps of EngineersAlbuquerque District
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More Information• Other Environmental Issues
10 lower-income apartment complex occurs in close proximity to the channel confluence of Spring Creek & Placitas Arroyo.
New Mexico's Air Quality reviews imply that the high ozone levels in the northwest and southern parts of the state are part of a regional problem.
VILLAGE OF PATCH, NM, FEASIBILITY STUDY
US Army Corps of EngineersAlbuquerque District
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VILLAGE OF PATCH, NM, FEASIBILITY STUDYCULTURAL RESOURCES
– During a site visit, black-on-white pottery fragments, burnt plant remains and long bones were observed eroding out of the river banks some 10 feet below the current floodplain.
– Another 2 feet below, a hard clay band was observed in the river bank profile in Placitas Arroyo.
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Plans Studied in Detail• No Action Plan• Non-Structural (Flood
Warning)• Channel Improvements• Flood Detention
o Upper Basin Structureo Lower Basin Structure
VILLAGE OF PATCH, NM, FEASIBILITY STUDY
US Army Corps of EngineersAlbuquerque District
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Project Alternatives• No Action Plan• Non-Structural (flood warning)• Non-Structural (raising/flood walls)• Non-Structural (buyouts/relocation)• Channel Improvements• Flood Detention
o Upper Basin Structureo Lower Basin Structure
VILLAGE OF PATCH, NM, FEASIBILITY STUDY
US Army Corps of EngineersAlbuquerque District
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Impact Comparison of Alternative Plans
Resource Area No Action Non Structural
NED Dam Channel Improvements
Land Use Farmland No Change to the Existing Condition
Some Change to the Existing Condition
Minimal impact to agricultural land
use due to location of structure.
High; Project located along agricultural
lands.
Transportation Existing Condition Minor Impact Temporary during Construction
High; numerous road crossings and reroutes.
Noise Existing Condition Existing Condition Temporary Temporary
Air Quality Existing Condition Existing Condition Temporary Temporary
Water Quality Existing Condition Improved Temporary Temporary
Settling Basin Existing Condition Existing Condition Hydrologic change Hydrologic Change
Vegetation/Wildlife Existing Condition Improved Minor Impact High
Cultural Resources Existing Condition Existing Condition Minor Impact Minor Impact
Visual Resources Existing Condition High Minor Impact High 19
Recommended PlanLocally Preferred Plan
100-yr (1% Event) Dam in Lower Basin
Features of the Locally Preferred Plan include• Earth fill Dam approximately 14,000 ft. in length• Concrete spillway 200 ft. in length• Height of approximately 20 ft.• Outlet Conduit• 300 Acre-Foot Sediment pool• 151 Acre-Foot Water Storage pool
VILLAGE OF PATCH, NM, FEASIBILITY STUDY
US Army Corps of EngineersAlbuquerque District
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Patch
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