Dam Report

Conowingo dam

Maryland, USA Susquehanna River Hazard High
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Dam height
94ft
Hazard rating
High
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Conowingo                                                         -- None dam
Conowingo None · Susquehanna River
About this dam

Conowingo

Conowingo Dam, located on the Susquehanna River in Port Deposit, Maryland, is a significant hydroelectric facility with a rich history dating back to its completion in 1928 by Stone & Webster Engineering Corp. The dam stands at a height of 94 feet and spans 4,648 feet, making it a vital structure for generating hydroelectric power and providing water supply and recreational opportunities in the area. With a storage capacity of 310,000 acre-feet and a drainage area of 27,077 square miles, Conowingo Dam plays a crucial role in managing water resources and flood control in the region.

The dam's controlled spillway, with a width of 3,036 feet, ensures the safe release of water during periods of high flow, while its 52 slide gates allow for efficient regulation of water levels. However, with a high hazard potential and very high risk assessment rating, Conowingo Dam faces challenges in maintaining its structural integrity and addressing potential safety concerns. Despite not being regulated by the state or subject to regular inspections, the Federal Energy Regulatory Commission oversees the dam's operations and inspections to ensure compliance with safety standards.

As a key player in the region's water management infrastructure, Conowingo Dam continues to be a focal point for water resource and climate enthusiasts. Its role in generating clean energy, providing recreational opportunities, and supporting water supply needs underscores the dam's importance in balancing environmental conservation with sustainable development. With its impressive engineering design and historical significance, Conowingo Dam remains a symbol of human ingenuity in harnessing the power of water for the benefit of the community and the environment.

StateNone
River / streamSusquehanna River
NID IDMD00097
Owner typeNot Listed
Primary purposeHydroelectric
Year built1928
Dam height94 ft
Dam length4,648 ft
Max storage310,000 AF
Normal storage301,400 AF
Surface area8,563.0 ac
Drainage area27,077.0 sq mi
Hazard potentialHigh
ConditionNot Available
Last inspectionWed, 30 Sep 2020 00:00:00 GMT

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 Conowingo -- inflows here typically show up in storage 24-72 hours later.

Track Conowingo 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.

FAQ

About Conowingo

Where does the data for Conowingo 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 High 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.