Bon Tempe Reservoir Water Level
The operating agency’s most recent report for Bon Tempe Reservoir is from November 19, 2023: a pool elevation of 715.6 ft and 3,776 acre-ft in storage. Newer readings will appear here as soon as they are published.
Bon Tempe
Bon Tempe is a reservoir located in Marin County, California, USA. It was built in 1949 and is part of the Marin Municipal Water District, providing water to 10,000 homes and businesses in the area. Bon Tempe is fed by surface water flowing from the Lagunitas Creek watershed, and its hydrology is impacted by the Mediterranean climate of the region. The reservoir is also dependent on the snowpack of Mount Tamalpais for its water supply. The area surrounding Bon Tempe is primarily used for recreational activities such as hiking, fishing, and camping. Additionally, the Bon Tempe reservoir plays an important role in maintaining the agricultural industry of Marin County by providing irrigation water to nearby farms.
Daily levels at Bon Tempe
Storage volume, pool elevation, and total release plotted from the operating agency's daily observations.
Storage
acre-ft · code 2
Pool Elevation
ft · code 1
Inside the reservoir
The real shoreline of this water body, with a depth model scaled so the basin holds exactly its recorded storage. Drag to orbit, scroll to zoom, and use the slider to drain and refill it. Click anywhere on the basin for the modelled depth there.
How this is built. The shoreline is the National Hydrography
Dataset polygon for this water body (“Bon Tempe Lake”),
matched to the dam by proximity and confirmed by comparing its area with the
National Inventory of Dams surface area.
Depth is modelled, not surveyed: the basin is shaped by distance from
shore — deep in open water, shallow in the bays — and scaled so its
volume equals the recorded storage. No national bathymetric survey exists for
US reservoirs. Treat the shoreline, area and volume as measured, and the depth
distribution as an informed approximation.
Above normal pool, water is shown rising within the normal-pool
shoreline. Where it would actually spread depends on the surrounding
terrain, which is not modelled here — a reservoir in a steep canyon barely
widens, one on flat ground can spread a long way. This is a depth and volume
figure, not an inundation map. Official inundation mapping for a dam
comes from its Emergency Action Plan.
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 Bon Tempe -- inflows here typically show up in storage 24-72 hours later.
| Streamgauge | Discharge | View |
|---|---|---|
| Corte Madera C A Ross Ca | 0 cfs | → |
| Redwood C A Hwy 1 Bridge A Muir Beach Ca | 0 cfs | → |
| Lagunitas C A Sp Taylor State Pk Ca | 9 cfs | → |
| Novato C A Novato Ca | 1 cfs | → |
| Olema C A Vedanta Bridge A Olema Ca | 0 cfs | → |
| Lagunitas C Nr Pt Reyes Station Ca | 9 cfs | → |
About Bon Tempe
What is the water level at Bon Tempe Reservoir right now?
The most recent report for Bon Tempe Reservoir is from November 19, 2023; no newer reading has been published. Daily levels and the year-over-year trend are shown on this page.
Is Bon Tempe Reservoir high or low right now?
Compare the percent-of-normal figure on this page: above 100% means storage is higher than the historical average for the date (a wet year), below 100% means lower (a dry year or drought). The daily-levels chart shows the current trend.
Where does the data for Bon Tempe come from?
Daily storage, pool elevation, and release rates are sourced from USGS, USBR, and USACE monitoring stations. Weather forecast comes from NOAA / yr.no -- the same feed Snoflo's iOS app uses.
How often is the report updated?
Storage observations are updated daily by the operating agency. The 15-day weather forecast refreshes throughout the day. Snoflo caches and renders the most recent observation -- check the "as of" timestamp on the storage card.
What does the Hazard 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 below 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 reservoir, set a threshold, and you'll get a push the moment conditions cross.