MCSWAIN
OperatingHydro power plant
- Capacity
- 9 MW
- Primary fuel
- Hydro
- County
- Mariposa County
- Operator
- MERCED IRRIGATION DISTRICT
- Status
- Operating
- Commissioned
- 1967
- EIA plant ID
- 410
- Coordinates
- 37.5221, -120.3101
MCSWAIN, a 9 MW Hydro power plant in Mariposa County, California. Operated by MERCED IRRIGATION DISTRICT, commissioned 1967.
Weather peril exposure
MCSWAIN is a 9 MW hydro power plant in Mariposa County, CA, operated by MERCED IRRIGATION DISTRICT, commissioned in 1967. Mariposa County carries moderate modeled catastrophe exposure in the FEMA National Risk Index, scoring 1.9 of 5 at the 23rd national percentile. Wildfire is the leading peril, rated Relatively High by FEMA at the 99th percentile.
The Bywatts loss layer is calibrated to solar PV hardware, so it is not applied to a hydro plant. The ratings below are the FEMA National Risk Index county hazard ratings for this location.
Mariposa County hazard ratings
| Peril | FEMA rating | National percentile | Peril score | Events per year |
|---|---|---|---|---|
| Wildfire | Relatively High | 99th | 5.0 of 5 | 0.02 |
| Riverine flooding | Relatively Low | 92nd | 4.7 of 5 | 2.1 |
| Heat wave | Relatively High | 88th | 4.5 of 5 | 6.1 |
| Earthquake | Relatively Low | 79th | 4.1 of 5 | 0.03 |
| Lightning | Relatively Moderate | 54th | 3.2 of 5 | 17.9 |
| Winter weather | Relatively Moderate | 36th | 2.4 of 5 | 12.7 |
| Strong wind | Very Low | 22nd | 1.9 of 5 | 0.05 |
| Tornado | Very Low | 7th | 1.3 of 5 | 0.12 |
| Hail | Very Low | 3rd | 1.1 of 5 | 0.15 |
Perils not assessed in Mariposa County
These perils carry no usable National Risk Index figure for this county, so they are excluded from the scoring rather than scored zero. A zero would claim the peril was assessed and found benign.
| Peril | Why it is not scored |
|---|---|
| Hurricane | FEMA rating is "Not Applicable" for this county |
| Coastal flooding | FEMA rating is "Not Applicable" for this county |
| Ice storm | FEMA rating is "Not Applicable" for this county |
Model hail, wind and flood exposure for Mariposa County in the weather risk calculator
Ratings are the FEMA National Risk Index county hazard ratings; the peril score is a Bywatts transform of the FEMA national percentile. Full data sources and the solar vulnerability methodology are in the weather risk calculator.
Modeled estimate for screening and negotiation. Built from FEMA National Risk Index county hazard data and a solar vulnerability layer documented above. Not a quote, a binder, or actuarial advice, and not a substitute for a carrier's own model. Hazard data: FEMA National Risk Index December 2025, synced 2026-07-24. Resolution is county level, not site level.