Dam Report

Crystal dam

California, USA Tr Crystal Crk Hazard High
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Tonight low
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Dam height
51ft
Hazard rating
High
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Crystal -- None dam
Crystal None · Tr Crystal Crk
About this dam

Crystal

Crystal is a privately owned dam located in St Helena, California, along the Tr Crystal Crk river/stream. Completed in 1952, this earth dam stands at a height of 51 feet and has a storage capacity of 105 acre-feet. The primary purpose of Crystal Dam is for water supply, with additional uses including irrigation and recreation. It is regulated by the California Department of Water Resources (DWR) and undergoes regular inspections to ensure its safety and compliance with state regulations.

With a high hazard potential, Crystal Dam is deemed to be in satisfactory condition as of the last assessment in September 2017. The dam is subject to annual inspections and has an emergency action plan in place, although details on its compliance with guidelines and the preparation of inundation maps are not specified. Despite these potential risks, Crystal Dam serves as a crucial water resource for the surrounding area, providing essential water supply for agricultural and recreational activities. Enthusiasts of water resources and climate will find interest in the history and operational aspects of this significant structure in Napa, California.

Overall, Crystal Dam is a vital component of the water infrastructure in Napa County, contributing to the region's water supply and supporting various purposes such as irrigation and recreation. Managed by a private entity, the dam is subject to state regulations and inspections to ensure its safety and functionality. As part of the Sacramento District, Crystal Dam plays a key role in the management and distribution of water resources in the area, highlighting the importance of sustainable water management practices in the face of climate challenges.

StateNone
River / streamTr Crystal Crk
NID IDCA00573
Owner typePrivate
Primary purposeWater Supply
Dam typeEarth
Year built1952
Dam height51 ft
Dam length475 ft
Max storage105 AF
Surface area8.0 ac
Drainage area0.1 sq mi
Hazard potentialHigh
ConditionSatisfactory
Last inspectionThu, 17 Dec 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 Crystal -- inflows here typically show up in storage 24-72 hours later.

Track Crystal 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 Crystal

Where does the data for Crystal 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.

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