How to Use This Report

What is this report?

Instead of combing the internet and clicking a million links to learn about water supply in Sheridan County, let us do the work for you! This report compiles many trustworthy sources into an easy-to-read and access report. It includes information about streamflow, snowpack, drought, soil moisture, and precipitation for both the Tongue and Powder Rivers. This report is a one-stop shop for information that can help you be aware of water in Sheridan to make decisions for your ranch and your land.

Helpful Hints:

• All forecasts have the word forecast underlined in the page's title.
• Each page has a little blurb at the top that gives you some helpful information.
• If you would like to know more about a topic, check out the sources at the bottom of the page!
• Sources are precise and bring you as close as possible to the original source.

Table of Contents

Drought Index and Change
Drought History and Forecast
Precipitation - Tongue River
Precipitation - Powder River
Reservoir Capacity and Stream Flow
Select Stream Flow Stations
Tongue Water Supply Forecast
Powder Water Supply Forecast
Temperature and Precipitation
Temperature Forecast and Precipitation Forecast
Vegetation Drought Responses and Soil Moisture

Drought Index and Change

The U.S. Drought Monitor gives you a broad overview of the drought conditions in the US. Its strength is bringing together many ways of determining drought. It is useful as a large-scale view of drought, but local drought resiliency efforts are not considered.

---

Sources:

​https://droughtmonitor.unl.edu/Maps/MapArchive.aspx​
​https://droughtmonitor.unl.edu/Maps/ChangeMaps.aspxhttps://droughtmonitor.unl.edu/Summary.aspx​

Table of contents

Drought History and Forecast

The first half of this page shows current conditions, followed by the forecast. The outlook is a prediction of

---

Sources:

​https://droughtmonitor.unl.edu/CurrentMap/StateDroughtMonitor.aspx?fips_56033​
​https://www.drought.gov/forecasts​
¹https://www.cpc.ncep.noaa.gov/products/expert_assessment/mdo_summary.php

https://www.cpc.ncep.noaa.gov/products/expert_assessment/mdo_discussion.php​
​https://droughtmonitor.unl.edu/Summary.aspx​

Table of contents

Precipitation - Tongue River

These graphs represent precipitation affecting the Tongue River. Snow water equivalent (SWE) represents the amount of water contained within the snowpack when it melts.

Sources:

​https://nwcc-apps.sc.egov.usda.gov/awdb/basin-plots/POR/WTEQ/assocHUCwy_8/tongue.html​
​https://nwcc-apps.sc.egov.usda.gov/awdb/basin-plots/POR/PREC/assocHUCwy_8/tongue.htm​

Table of contents

Precipitation - Powder River

These graphs represent precipitation affecting the Powder River watershed. Snow water equivalent represents the amount of water contained within the snowpack when it melts.

Sources:

​https://nwcc-apps.sc.egov.usda.gov/awdb/basin-plots/POR/WTEQ/assocHUCwy_8/powder.html​
​https://nwcc-apps.sc.egov.usda.gov/awdb/basin-plots/POR/PREC/assocHUCwy_8/powder.html​

Table of contents

Reservoir Capacity and Stream Flow

The total capacity of reservoirs and current water storage includes inactive storage below the outlet.

Lake DeSmet

As of December 1, Lake DeSmet has a total of 195,414 acre-feet in storage. 

Reservoir	Total Storage (Acre-ft)	Current Storage (Acre-ft)	Percentage of Total Capacity (%)
Bighorn	4,624	1,041
Cross Creek	824	186
Dome Lake No. 1	1,506	851
Kearney Lake	6,324	959
Park Lake	10,362	3,450
Sawmill	1,275	759

Tongue River Reservoir

Water levels relatively remained unchanged overall from the last month at 44,577 acre-feet. The reservoir is 56.4% full.

This graph displays the real time data of the Tongue River Reservoir. This data remains provisional until it is officially reviewed due to variables that can affect the gages. These include but are not limited to algal and aquatic growth, sediment movement, malfunction of recording equipment, and back water from ice or debris such as log jams.

Sources:

Lake DeSmet Operating Department at lakedesmet@johnsoncowy.us​
​https://seoflow.wyo.gov/Data/Map/Parameter/Total%20Storage/Location/Identifier/Interval/Latest​
​https://gis.dnrc.mt.gov/apps/stage/gage-report/location/3f087fe86bde421f857dfedff4e40e93/1680476400000-1683154740000​

Table of contents

Select Stream Flow Stations

These graphs give context to stream flow percentile classes. The selected USGS stream gauges are on the stateline with Montana, being the downstream end of the Tongue and Powder within our region. The flow represent average 7-day flows. The vertical axis is logarithmic meaning it goes up by 10x for each major tick mark.

---

Sources:

​https://waterwatch.usgs.gov/index.php?id=mv01d​
​https://waterwatch.usgs.gov/?id=wwchart_sitedur&ofmt=plot_mvbg&site_no=06306300​
​https://waterwatch.usgs.gov/?id=wwchart_sitedur&ofmt=plot_mvbg&site_no=06324500​

Table of contents

Temperature and Precipitation

Temperature and precipitation are large drivers of changes in drought conditions. As you might expect, high temperatures and low precipitation can worsen drought conditions while low temperature and high precipitations can improve them.

---

Sources:

​https://www.cpc.ncep.noaa.gov/products/tanal/temp_analyses.php​
​https://www.cpc.ncep.noaa.gov/products/Global_Monsoons/American_Monsoons/NAMS_precip_monitoring.shtml2​
​https://www.cpc.ncep.noaa.gov/products/expert_assessment/mdo_discussion.php3​
​https://www.weather.gov/byz/daily_records?city=Sheridan​

Table of contents

Temperature Forecast and Precipitation Forecast

https://www.cpc.ncep.noaa.gov/products/predictions/long_range/lead14/interactive/index.php Explore link above for an Interactive map that displays percentage chance above and below normal for any point in US

---

Sources:

​https://www.cpc.ncep.noaa.gov/​
​https://www.cpc.ncep.noaa.gov/products/predictions/long_range/lead14/interactive/index.php –Interactive with percentages​
​https://www.cpc.ncep.noaa.gov/products/expert_assessment/mdo_discussion.php​

Table of contents

Vegetation Drought Responses and Soil Moisture

The graphs below are two ways of visualizing on-ground conditions. The vegetation Drought Response Index (Vegdri) uses a satellite to estimate vegetative stress. Soil moisture is helpful when looking at many things. Soil acts as a bank for moisture and can buffer drought degradation or improvement. It is also the water that plants have available to them so is linked to vegetative stress.

---

Sources:

​https://vegdri.unl.edu/Home/VegDRIQuad.aspx?WY,2​
​https://www.cpc.ncep.noaa.gov/products/Soilmst_Monitoring/US/Soilmst/Soilmst.shtml​
​http://www.wrds.uwyo.edu/Soil/SM-Ptile-Current.html​

Table of contents

Additional Resources

These are the broad sources we got information from. These websites are trustworthy and are reliable sources for additional information. In the future we hope to add more source for additional information.

• https://droughtmonitor.unl.edu
• https://www.drought.gov
• https://www.cpc.ncep.noaa.gov
• https://www.nrcs.usda.gov/wps/portal/wcc/home
• https://waterwatch.usgs.gov
• Lake DeSmet Operating Department at lakedesmet@johnsoncowy.us
• http://dnrc.mt.gov/divisions/water/projects/tongue-river
• https://seoflow.wyo.gov/Data/Map/Parameter/Total%20Storage/Location/Identifier/Interval/Latest
• https://vegdri.unl.edu/Home/VegDRIQuad.aspx?WY,2