Lake Francis Case
Lake Francis Case is managed by U.S. Army Corps of Engineers — Omaha District. Published reference elevations are listed below.
Lake Status
We don't have enough recent gauge readings to summarize Lake Francis Case's status yet. View the water level page for the latest published data.
Watershed drought conditions
Gregory County, SD · surrounding county from lake location
Moderate Drought
Moderate drought is affecting the watershed.
Severity
Weekly trend
Improving
Compared with last week
Official drought
Yes
80.5% of the watershed is currently classified as official drought (D1+).
Expected impacts
- Stream inflows may run below normal
- Lake levels can decline faster between rain events
- Vegetation stress may increase over time
U.S. Drought Monitor · map date Sep 8, 2026. Updated weekly. droughtmonitor.unl.eduView drought map for Gregory County, SD
Key Facts
Managing authority
Waterbody / project type
Official purposes
Full pool
Datum
Project / NID identifier
Dam / watershed (NID design values)
Static design values from a confidently matched National Inventory of Dams record — not live gage readings.
- Normal storage
- 43 acre-ft
- Max storage
- 75 acre-ft
- Spillway capacity (design)
- 3,400 cfs
- Dam structure
- Earth · 23 ft high · completed 1957
- Hazard classification
- Low
National Inventory of Dams · matched record: Francis Chaffee Dam No.1 (SD01013)
How this lake is operated
- Documented project purposes (National Inventory of Dams): Fire Protection, Stock, Or Small Fish Pond.
Why the level can change
General factors for reservoirs like this
These are common influences for this type of lake. They do not identify the cause of a specific current change unless an operator update confirms it.
Rainfall & inflows
Rain and upstream river inflows can raise reservoir levels, especially after storms.
Downstream releases
When an operator releases water through a dam, reservoir storage can fall and downstream flows can rise.
Flood-risk operations
Some projects store or release water under flood-risk rules when conditions require it.
Water supply
Some reservoirs support municipal, industrial, irrigation, or regional water-supply needs.
Hydropower
Hydropower projects may pass water through turbines when generating electricity.
Seasonal weather
Dry periods, heat, evaporation, and seasonal rainfall patterns can affect storage over weeks and months.
Published reference elevations
- Full pool
- 1350.00 ft
Published reference elevation. Not necessarily a fixed year-round target for every project.
Current data source
Managing authority: U.S. Army Corps of Engineers — Omaha District
Observation source used by Lake Insights: Not published
Who manages the lake and who publishes the reading Lake Insights displays can differ. Lake Insights does not invent a source label from the managing authority alone.
General education
Shared background — not lake-specific facts
Lake Insights aggregates water level information from authoritative public sources such as the U.S. Army Corps of Engineers, NOAA, TVA, Bureau of Reclamation, power utilities, and other official lake operators. We preserve historical observations, calculate trends, and present lake conditions in a consistent format. Lake Insights does not predict future lake levels unless an official forecast has been published by the managing authority.
Common questions about Lake Francis Case
- Who manages Lake Francis Case?
- Lake Francis Case is managed by U.S. Army Corps of Engineers — Omaha District. Lake Insights reports published gauge readings; it does not operate the waterbody.
- What is full pool at Lake Francis Case?
- The published full-pool elevation for Lake Francis Case is 1350.00 ft (NGVD29). Full pool is a published reference elevation — not a prediction of today’s level.
- What datum is used for Lake Francis Case?
- Elevations for Lake Francis Case are referenced to NGVD29 (MSL).
- What are the documented purposes of Lake Francis Case?
- Documented purposes for Lake Francis Case (National Inventory of Dams): Fire Protection, Stock, Or Small Fish Pond.