Delavan #2 (Grist Mill) dam
Delavan #2 (Grist Mill)
Delavan #2, also known as Grist Mill or Comus Lake, is a gravity dam located in Walworth, Wisconsin. Built in 1947 for recreational purposes, this dam stands at a height of 13 feet with a hydraulic height of 7 feet. The dam spans a length of 1054 feet and has a storage capacity of 850 acre-feet, with a normal storage level of 606 acre-feet. The dam is situated on the SOUTH BR TURTLE CREEK, serving as a popular spot for outdoor activities in the region.
Despite being classified as having a low hazard potential, Delavan #2 has not been rated for its condition assessment since its last inspection in 1986. The dam is state-regulated by the Wisconsin Department of Natural Resources (WIDNR) and is subject to state permitting, inspection, and enforcement. With its proximity to the city of DELAVAN and its contribution to the local drainage area of 51.6 square miles, Delavan #2 plays a significant role in the water resource management of the region.
For water resource and climate enthusiasts, Delavan #2 offers an intriguing case study of a historic gravity dam that continues to provide recreational opportunities while facing challenges in terms of maintenance and assessment. Its location, design, and state oversight make it a focal point for discussions on dam safety, environmental impact, and the sustainable use of water resources in the state of Wisconsin.
Dam data reference
Condition Assessment
- Satisfactory
- No existing or potential dam safety deficiencies are recognized. Acceptable performance is expected under all loading conditions (static, hydrologic, seismic) in accordance with the minimum applicable state or federal regulatory criteria or tolerable risk guidelines.
- Fair
- No existing dam safety deficiencies are recognized for normal operating conditions. Rare or extreme hydrologic and/or seismic events may result in a dam safety deficiency. Risk may be in the range to take further action.
- Poor
- A dam safety deficiency is recognized for normal operating conditions which may realistically occur. Remedial action is necessary. POOR may also be used when uncertainties exist as to critical analysis parameters which identify a potential dam safety deficiency.
- Unsatisfactory
- A dam safety deficiency is recognized that requires immediate or emergency remedial action for problem resolution.
- Not Rated
- The dam has not been inspected, is not under state or federal jurisdiction, or has been inspected but, for whatever reason, has not been rated.
Hazard Potential Classification
- High
- Dams assigned the high hazard potential classification are those where failure or mis-operation will probably cause loss of human life.
- Significant
- Dams assigned the significant hazard potential classification are those dams where failure or mis-operation results in no probable loss of human life but can cause economic loss, environmental damage, disruption of lifeline facilities, or impact other concerns. Significant hazard potential classification dams are often located in predominantly rural or agricultural areas but could be in areas with population and significant infrastructure.
- Low
- Dams assigned the low hazard potential classification are those where failure or mis-operation results in no probable loss of human life and low economic and/or environmental losses. Losses are principally limited to the owner's property.
- Undetermined
- Dams for which a downstream hazard potential has not been designated or is not provided.
Plan around the weather
Same NOAA / yr.no feed Snoflo's iOS app uses. Watch the precipitation column on the meteogram -- rain on the basin upstream typically lifts inflow 24-72 hours later.
Next 5 days, hour by hour
Temperature line with weather symbols on top, snow + rain accumulation as columns, humidity as a dotted line.
5-day forecast table
Every 3 hours, broken out across temperature, snow, rain, humidity, and wind. Each cell is colour-coded relative to the column min/max.
| Time | Condition | Temp (°F) | Snow (in) | Rain (in) | Humidity (%) | Wind (mps) | Wind dir |
|---|---|---|---|---|---|---|---|
| Loading detailed forecast… | |||||||
15-day temperature & precipitation
Daily temperatures, snow, and rain projected over the next two weeks.
Nearby streamflow gauges
USGS streamgauges around Delavan #2 (Grist Mill) -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Jackson Creek At Mound Road Near Elkhorn | 4 cfs | → |
| Piscasaw Creek Near Walworth | 3 cfs | → |
| Turtle Creek At Carvers Rock Road Near Clinton | 194 cfs | → |
| White River At Center Street At Lake Geneva | 0 cfs | → |
| Rock River At Afton | 3,240 cfs | → |
| Fox River Near New Munster | 500 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Delavan #2 (Grist Mill).
Boat launches
- Comus Lake -- Access
- Lake Delavan -- Access - Shore Rd.
- Delavan Lake -- 400 Inlet Shore Drive
- Delavan Lake -- Access Off State Hwy 50
- Turtle Lake Public Boat Launch
- Barkers Road Town Of Sugar Creek
Campgrounds
- Lake Geneva Youth Camp
- Tent Camping @ Big Foot Beach State Park
- Rv Camping @ Big Foot Beach State Park
- Kmsf-Su Shelter 3
- Kmsf-Su Shelter 2
- North Branch Conservation Area (Cyclists Only)
Fishing spots
Track Delavan #2 (Grist Mill) in the Snoflo app
Save this dam as a favorite and get the local NOAA / yr.no forecast plus regional flow context wherever you are.
About Delavan #2 (Grist Mill)
Where does the data for Delavan #2 (Grist Mill) come from?
Structural and regulatory data come from the U.S. Army Corps of Engineers' National Inventory of Dams (NID). Weather forecast comes from NOAA / yr.no -- the same feed Snoflo's iOS app uses.
How often is the report updated?
NID structural data refreshes annually as the Corps publishes updated assessments. The weather forecast refreshes throughout the day.
What does the Low hazard rating mean?
The Corps of Engineers' hazard potential classification grades probable consequences if the dam fails: High = probable loss of human life; Significant = no probable loss of human life but possible economic loss / environmental damage; Low = no probable loss of human life, only minor economic / environmental losses. See the Dam Data Reference card above for the full definitions.
What's "% of normal"?
The current storage value compared to the historical average storage on this calendar day. 100% = right on average; values above 100% mean above-normal storage (wet year); values below mean below-normal (dry year or drought).
Can I get alerts when storage crosses a threshold?
Yes -- alerts are managed in the Snoflo iOS app. Favorite this dam, set a threshold, and you'll get a push the moment conditions cross.
Other water bodies near here
Snoflo-tracked reservoirs and dams within driving distance of Delavan #2 (Grist Mill).