Kansas Water in 2020: Wet Start, Normal Finish, Worsening Drought

Water year 2019 precipitation as a percentage of normal (1981–2010). NOAA data, map by the U.S. Geological Survey.

The network

The U.S. Geological Survey (USGS), with federal, state and local partners, runs a long-term network of monitoring stations in Kansas — in water year 2020, 219 real-time streamgages, 12 real-time reservoir-level stations and 20 groundwater stations. (A water year runs October 1 to September 30, named for the year it ends in.) Staff check the real-time data through the year with regular measurements, and each year's conditions are compared with the full record. The data serve water management, protection of life and property, reservoir operations, farming, public supply, ecological studies, industry and recreation.

Rain

2019 was wetter than normal across the state, with normal to much greater than normal runoff. 10 of the 12 reservoirs USGS monitors began 2020 above their full conservation pool.

In 2020, some areas got more rain than normal and some less; every major basin had a mix. The pattern: wetter in the north-central and northeast, drier in the far west and southeast. Even so, with near-normal rain overall, drought intensified across much of the state.

Water year 2020 precipitation as a percentage of normal (1981–2010). U.S. Geological Survey.

Departure from normal precipitation, in inches, water year 2020. U.S. Geological Survey.

Kansas always has a steep east–west gradient: in 2020 the far west got 10–20 inches, the far east 35–50, and small areas 50–60.

Observed precipitation, water year 2020. National Oceanic and Atmospheric Administration.

Runoff and streamflow

Runoff — flow per unit of area, estimated from gaged streams — characterizes large areas. In 2020 it was normal to much greater than normal: it started the year far above normal, fell into the normal range by summer, and neared slightly below normal in September, as rain ran mostly below normal from May on — and drought had spread by the year's end.

Statewide runoff, water year 2020: cumulative (A) and monthly (B). U.S. Geological Survey.

Streamflow ranged from extremely low to extremely high percentiles. The southwest stayed below to much below normal all year; elsewhere, conditions varied widely.

Monthly streamflow conditions across Kansas through water year 2020. U.S. Geological Survey.

Reservoirs

USGS monitors the level and contents of 12 reservoirs.

• Over 100 percent above the conservation pool at the start, after the wet 2019: Milford, Kanopolis, Tuttle Creek, Perry, Clinton and Pomona Lakes.
• Above the pool, but under 120 percent: Wilson, Melvern and Hillsdale Lakes.
• Below full: Cedar Bluff, HorseThief and Cheney.

By the end of the year, most had dropped below their conservation pools. Four of the larger reservoirs, among them Milford, Tuttle Creek and Perry, ended still above a full pool but with more than 40 percent less water than they began with. Only HorseThief gained storage. Cedar Bluff stayed lowest: with little inflow it relies heavily on rain and releases little except in heavy rain, so its storage changes less than the others'.

Reservoir contents, water year 2020. U.S. Geological Survey.

In short

Kansas started 2020 with above-normal streamflow after a wet 2019, and ended it with streamflow generally normal after a year of near-normal rain.

Sources

Based on Hydrologic Conditions in Kansas, Water Year 2020, U.S. Geological Survey Fact Sheet 2021–3045, by Chantelle Davis, USGS Publications Warehouse; a work of the United States government in the public domain. The fact sheet names Hillsdale Lake in one place and Clinton Lake in another as the fourth reservoir that ended above its pool; this page names only the three both lists share. Maps and charts recovered from the fact sheet's PDF; its drought maps, from the National Drought Mitigation Center, are not reproduced.