Dam Report

Zellmer Subwtrshd Sta 31+70 #M dam

Iowa, USA Tr-West Fork Little Sioux Riv Hazard Low
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Dam height
42ft
Hazard rating
Low
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Zellmer Subwtrshd Sta 31+70 #M -- None dam
Zellmer Subwtrshd Sta 31+70 #M None · Tr-West Fork Little Sioux Riv
About this dam

Zellmer Subwtrshd Sta 31+70 #M

Zellmer Subwtrshd Sta 31+70 #M is a local government-owned dam located in Woodbury County, Iowa, specifically in the city of ROLLY SPRINGS. Constructed in 1964 by the USDA NRCS, this earth dam has a height of 42 feet and a length of 407 feet, with a primary purpose of providing fire protection, stock, or small fish pond, as well as flood risk reduction. With a normal storage capacity of 19 acre-feet and a drainage area of 0.18 square miles, this dam serves as a valuable resource for the surrounding community.

Managed by the Iowa Department of Natural Resources, Zellmer Subwtrshd Sta 31+70 #M is regulated by state authorities for inspection, permitting, and enforcement. The dam has a low hazard potential and is currently rated as "Not Rated" in terms of condition assessment, with a moderate risk level identified. While it does not have a specific Emergency Action Plan (EAP) prepared, the dam has not undergone any recent modifications and has not required any major risk management measures to be implemented. Overall, this dam plays a crucial role in water resource management and protection in the area.

Located along the TR-WEST FORK LITTLE SIOUX RIV, Zellmer Subwtrshd Sta 31+70 #M provides important benefits for fire protection, stock water supply, and flood risk reduction in the region. With a focus on maintaining public safety and environmental sustainability, this dam stands as a key infrastructure for water resource and climate enthusiasts to monitor and support.

StateNone
River / streamTr-West Fork Little Sioux Riv
NID IDIA01242
Owner typeLocal Government
Primary purposeFire Protection, Stock, Or Small Fish Pond
Dam typeEarth
Year built1964
Dam height42 ft
Dam length407 ft
Max storage34 AF
Normal storage19 AF
Surface area1.9 ac
Drainage area0.2 sq mi
Hazard potentialLow
ConditionNot Rated

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.
Detailed forecast

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.

Hourly detail

Next 5 days, hour by hour

Temperature line with weather symbols on top, snow + rain accumulation as columns, humidity as a dotted line.

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Deep dive

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.

TimeConditionTemp (°F)Snow (in)Rain (in)Humidity (%)Wind (mps)Wind dir
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Long-term outlook

15-day temperature & precipitation

Daily temperatures, snow, and rain projected over the next two weeks.

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Regional inflow

Nearby streamflow gauges

USGS streamgauges around Zellmer Subwtrshd Sta 31+70 #M -- inflows here typically show up in storage 24-72 hours later.

Track Zellmer Subwtrshd Sta 31+70 #M in the Snoflo app

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FAQ

About Zellmer Subwtrshd Sta 31+70 #M

Where does the data for Zellmer Subwtrshd Sta 31+70 #M 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.

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Manage alerts in the Snoflo app

Custom alerts are configured in the iOS app -- favorite this dam, set a threshold, and you'll get a push the moment conditions cross.

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