Held Watershed Site D-4 dam
Held Watershed Site D-4
Held Watershed Site D-4 in Plymouth, Iowa, is a crucial Earth dam completed in 1978 for fire protection, stock, and small fish pond purposes. This site, managed by the local government and designed by the USDA NRCS, lies along the TR-Floyd River and serves multiple functions including flood risk reduction. With a dam height of 33 feet and a storage capacity of 123 acre-feet, this 450-foot long structure covers an area of 6.4 acres and drains a watershed area of 0.44 square miles.
Despite its low hazard potential, Held Watershed Site D-4 has a moderate risk assessment score of 3, indicating the need for ongoing monitoring and risk management measures. The dam is state-regulated by the Iowa DNR, with permitting, inspection, and enforcement conducted by state authorities. While the condition assessment is currently not rated, the site's emergency action plan (EAP) status is unclear, suggesting a potential area for improvement in terms of preparedness and response in case of emergencies.
Located just 2 miles from Hinton, Iowa, this site is a significant component of the local water resource infrastructure, providing essential services for both community safety and environmental conservation. With its strategic position along the TR-Floyd River and its multi-purpose design, Held Watershed Site D-4 represents a vital asset in the sustainable management of water resources and climate resilience efforts in the region.
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 Held Watershed Site D-4 -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Floyd River At James | 323 cfs | → |
| Perry Creek Near Milnerville | 25 cfs | → |
| Missouri River At Sioux City | 26,000 cfs | → |
| Big Sioux River At Akron | 1,120 cfs | → |
| Omaha Cr At Homer | 31 cfs | → |
| Floyd River At Alton | 65 cfs | → |
Make a day of it
Boat launches, lakeside camping, fishing access, and other reservoirs near Held Watershed Site D-4.
Boat launches
- Bacon Creek Sioux City
- Scenic Park S Sioux City
- 220th Street Plymouth County
- Crystal Cove Park
- Dakota City
- 180th Street Plymouth County
Track Held Watershed Site D-4 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 Held Watershed Site D-4
Where does the data for Held Watershed Site D-4 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 Held Watershed Site D-4.