Key points
- Nationally, an average year. Runoff averaged 8.91 inches, close to the long-term mean of 9.29 inches. Water year 2014 ranked 52nd of 85 years (1 = wettest).
- The Southwest was dry. California and Arizona were much below normal; Nevada, Nebraska, Kansas, Oklahoma, New Mexico, Texas and Puerto Rico below normal.
- The north-central states were wet. Montana, the Dakotas, Wisconsin, Michigan, Ohio, New York, Maryland and Delaware were above normal.
- Record lows came in Nebraska (winter) and Arizona (spring).
About this summary
These maps and graphs describe streamflow in water year 2014 (October 1, 2013, to September 30, 2014), set against the 85 years from 1930 to 2014 — before 1930 there were too few streamgages to represent most regions. The data come from the USGS National Streamflow Information Program.
- Runoff is the depth of water that would cover an area if all its streamflow over a period were spread evenly across it. It lets flow be compared between places of different size.
- Ranks: 1 is the highest flow of all 85 years; 85 the lowest.
| Rank | Class |
|---|---|
| 85 | lowest |
| 78–84 | much below normal |
| 65–77 | below normal |
| 22–64 | normal |
| 9–21 | above normal |
| 2–8 | much above normal |
| 1 | highest |
For Puerto Rico, 71 years of data were available.
The nation
Annual mean U.S. runoff, 1930–2014. USGS.
Statewide streamflow ranks, water year 2014. USGS.
Most states were in the normal range. (Earlier summaries, before 2011, compared median rather than average runoff.)
By region
The country, with Puerto Rico and the Virgin Islands, is divided into 21 water resources regions — large drainages based on the land's surface: the basin of one major river such as the Columbia, the combined basins of several rivers such as the Texas–Gulf region, or an island group. They give a watershed-based way to map streamflow.
| Condition | Regions |
|---|---|
| Much below normal | California (18) |
| Below normal | Great Basin (16), Lower Colorado (15), Rio Grande (13), Texas–Gulf (12), Puerto Rico (21) |
| Above normal | Souris–Red–Rainy (09), Upper Mississippi (07), Great Lakes (04) |
Water resources region streamflow ranks, water year 2014. USGS.
Season by season
| Season | National rank | Low | High |
|---|---|---|---|
| Autumn (Oct–Dec 2013) | 54th | California much below normal; Washington, Oregon, Utah, Arizona, Iowa, Florida, Massachusetts, Rhode Island and Hawaii below | North and South Dakota much above; Kentucky, Ohio, West Virginia, Maryland, D.C. and Delaware above |
| Winter (Jan–Mar 2014) | 68th | Nebraska at a record low (85th of 85); much below or below normal across the South and Southwest — California, Arizona, Nevada, Utah, New Mexico, Texas, Oklahoma, Kansas, Louisiana, Missouri, Mississippi — and Wisconsin | Maryland, Alaska, D.C. and Delaware above |
| Spring (Apr–Jun 2014) | 23d | Arizona at a record low (85th of 85); California, Nevada, Utah, New Mexico, Texas, Oklahoma and Puerto Rico below or much below | Much above in Minnesota, Wisconsin, Michigan, Ohio, Maryland, D.C., Mississippi and Alabama; above in Montana, North Dakota, Indiana, Pennsylvania, New York, Vermont, Connecticut, New Jersey, Delaware, Virginia, Georgia and Florida |
| Summer (Jul–Sep 2014) | 36th | California, Texas, Alabama, Georgia, South Carolina and Alaska below or much below | the Dakotas, Minnesota, Iowa, Wisconsin, Illinois, Michigan, New York, New Hampshire, Maine, Arkansas and D.C. above |
Autumn (October–December 2013). USGS.
Winter (January–March 2014). USGS.
Spring (April–June 2014). USGS.
Summer (July–September 2014). USGS.
Highs and lows
Monthly extremes. In a typical month, about 5% of streamgages record very high flow (above the 95th percentile) and 5% very low (below the 5th). In water year 2014:
- only May had more very high flows than expected (8%);
- four months had more very low flows than expected — December (6%), January (8%), April (6%) and May (6%).
Streamgages with very high and very low monthly streamflow, October 1999–September 2014. USGS.
Floods. Bankfull flow is the highest daily mean flow expected, on average, once every 2.3 years. In 2014, 34% of streamgages exceeded it — fewer than the 43% expected in a typical year. The most since 1950 was 69%, in 1996.
Streamgages above bankfull streamflow, 1950–2014. USGS.
Droughts. The 10th-percentile 7-day low flow is the lowest 7-day average expected once every 10 years. In 2014, only 5% of streamgages fell below it, against 10% expected. The most since 1950 was 24%, in 1954.
Streamgages below the 10th-percentile annual 7-day minimum streamflow, 1950–2014. USGS.
The streamgage network
The USGS runs about 8,124 streamgages, most reporting in real time, funded with 850 federal, state, tribal and local partner agencies through the National Streamflow Information Program and the Cooperative Water Program. Their data serve water management, flood and drought monitoring, bridge design and recreation.
- Current conditions: WaterWatch
- Real-time and historical data: NWIS
Sources
Based on Xiaodong Jian, David M. Wolock, Harry F. Lins and Steve Brady, "Streamflow of 2014: Water year summary," U.S. Geological Survey Fact Sheet 2015–3026 (2015); a work of the United States government in the public domain. The maps and graphs are taken from the fact sheet's PDF. The source describes the network as "nearly 8,124" streamgages.
Licence: CC0 1.0 (public domain) · Adapted from pubs.usgs.gov
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