After the Fire, Before the Flood: How Much Sediment Reaches Acequia Headgates, and What Cuts It?

After the Frijoles Fire burned about 15,000 acres in the Santa Cruz and Rio Frijoles watersheds, heavy rain started washing ash and dirt into the acequias near Española. In August 2025, storms filled about 30 ditches with sludge, and the damage in the Santa Cruz area was estimated at close to $3 million. A lot of these acequias are run by small groups of volunteers, so they do not have much money to dig the ditches out or to deal with disaster paperwork. While the ditches stay clogged, farms do not get water.

My project asks how much sediment reaches an acequia headgate during a storm after a fire, and whether things like reseeding, check dams, or thinning the forest would lower that amount.

Acequias are old community ditches that carry water to fields. When a fire kills plants and makes the soil harder for water to soak into, rain runs downhill faster and picks up ash and loose dirt. Nineteen ditches around Chimayó were damaged in August 2025, and Rio Arriba County declared an emergency for places including Chimayó, Hernandez, La Madera, and Ojo Caliente. People are already trying to slow floodwater in the Lower Rio Chama area, but there is not a simple local model that shows how much sediment one storm might send into a ditch.

For this project I would split the watershed into small cells and give each cell a slope, a burn level, and a soil type. Then I would use rainfall data to estimate how much water soaks in, how much runs off, and how much sediment moves downhill to the headgate. I would run the model again with restoration added and compare the results to real damage reports. The data I need includes burn-severity maps, storm rainfall, elevation, soil information, and damage estimates. If it works, the model should show which restoration idea cuts sediment the most and which parts of the watershed cause the biggest problems. That could help acequia members and the county decide where repairs and restoration would do the most good before the next storm.