HATCH, NM, Background Information Village of Hatch Case Study

The study area is located in Hatch, NM. The historical problems of record are associated with flooding and the related consequences. Structures and roadways have been impacted by flows from the surrounding mountains, significantly flooding the community several times in the past 10-years. Flooding originates from two sources-Spring Canyon and Placitas Arroyo. Initial investigations determined that there is a likely Federal interest in a project to manage the flood risk in the community. Your instructions are to determine the planning objectives, measures to meet the objective(s),, formulation strategies to combine the measures and alternative plan(s). Regional Setting

Drainage Area

Floodplains

Flood History: The Village of Hatch experienced significant Flood events in 1988, 2002 and FEMA and Corps’ analyses determined Spring Canyon is a flood threat to the Village of Hatch. The entire Village of Hatch lies within a “100-year” Floodplain

Flood Potential: Spring Canyon channel capacity is 1,300 CFS (100- year flow is-1% chance event-estimated at 2,600 CFS) Estimated average annualized flood damages of $1.1 million from Spring Canyon

Existing and Likely Future Without-Project Conditions Physical Setting 7.2 square mile watershed draining from the south flowing north into the Rio Grande An upstream detention structure controls 5.4 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 More than 50% of buildings are at least 50-years old The riparian ecosystem along the channels are degraded and subject to land use modifications 70% of households median income is at or below the US poverty level

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 perhaps sized for a 5-year event. Lack of O&M (no money to pay for O&M) and sediment renders the system largely inoperable during larger events.

Existing and Likely Future Without-Project Conditions Social and Economic Conditions 2004 population of 1, single residential structures within the 1% event floodplain 87 commercial structures within the 1% event floodplain 27 public structures within the 1% event floodplain 1 apartment within the 1% event floodplain

Existing and Likely Future Without-Project Conditions Social and Economic Conditions (continued) Median income for a household: $16,100 Many seasonal inhabitants “Chile capitol of the world” 72 homes with flood insurance

More Information Non-damaging Channel Capacity 1,300 cubic feet per second (cfs) 100-year flow 2,600 cfs Flood Damages Estimated average annualized flood damages $1.1 Mil Federal Disaster Area in 2006