Annual runoff in the Nation’s rivers and streams during water year 2022 (8.97 inches) was slightly lower than the long-term (1930–2022) mean annual runoff of 9.39 inches for the contiguous United States (fig. 1). Nationwide, the 2022 annual mean streamflow ranked the 60th highest out of the 93 years.

Figure 1. Annual runoff in the contiguous United States, water years 1930–2022.

Annual mean streamflow also was ranked by State, which in this summary includes the District of Columbia, and Puerto Rico combined with the Virgin Islands. Streamflow was much below normal in Hawaii and Utah (fig. 2). Streamflow was below normal in Arizona, California, Colorado, Maryland, Nevada, North Carolina, Texas, Virginia, and Wyoming. Streamflow was above normal in Indiana, Kentucky, North Dakota, and Ohio.

Figure 2. Statewide streamflow ranks of the United States for water year 2022 compared to annual streamflows for water years 1930–2022.[Some colors in the explanation may not be used on the map; **, for Puerto Rico and the Virgin Islands, 79 years of available data were used and the rank was adjusted accordingly]

The United States, the District of Columbia, and Puerto Rico combined with the Virgin Islands lie in 21 large drainages, or water-resources regions (fig. 3). These water-resources regions are based on surface topography and contain the drainage area of a major river; the combined drainage areas of a series of rivers, such as the Texas-Gulf region, which includes several rivers draining into the Gulf of Mexico; or the area of an island or island group. Water-resources regions provide a coherent, watershed-based framework for depicting streamflow variations.

Figure 3. Water-resources regions of the United States.

Annual streamflow was ranked much below normal in the Hawaii and Great Basin regions (fig. 4). Annual streamflow was ranked below normal in the Upper Colorado, Texas-Gulf, and California regions. Annual streamflow was ranked above normal in the Ohio region. Annual streamflow was ranked much above normal in the Souris-Red-Rainy region.

Figure 4. Regional streamflow ranks in the United States for water year 2022 compared to annual streamflows for water years 1930–2022.[Some colors in the explanation may not be used on the map; **, for Puerto Rico and the Virgin Islands, 79 years of available data were used and the rank was adjusted accordingly]

Autumn (October–December 2021) streamflow was ranked below normal in Alaska, Arizona, Colorado, New Mexico, North Carolina, Puerto Rico and the Virgin Islands, Utah, Virginia, West Virginia, and Wyoming (fig. 5). Streamflow was ranked above normal in Connecticut, Illinois, Indiana, Massachusetts, Michigan, Ohio, and Vermont. Streamflow was ranked much above normal in New York and Washington. Nationwide, autumn-season streamflow ranked the 42d highest out of 93 years.

Figure 5. Autumn (October–December 2021) statewide streamflow ranks in the United States compared to autumn streamflows for water years 1930–2022[Some colors in the explanation may not be used on the map; **, for Puerto Rico and the Virgin Islands, 79 years of available data were used and the rank was adjusted accordingly]

Winter (January–March 2022) streamflow was ranked much below normal in California, Colorado, Hawaii, New Mexico, and Utah (fig. 6). Streamflow was ranked below normal in Arizona, Delaware, Iowa, Louisiana, Maryland, Nevada, New Jersey, Oregon, Texas, and Wyoming. Streamflow was ranked above normal in Alabama, Indiana, Kentucky, New Hampshire, Ohio, Tennessee, and Vermont. Nationwide, winter-season streamflow ranked the 57th highest out of 93 years.

Figure 6. Winter (January–March 2022) statewide streamflow ranks in the United States compared to winter streamflows for water years 1930–2022[Some colors in the explanation may not be used on the map; **, for Puerto Rico and the Virgin Islands, 79 years of available data were used and the rank was adjusted accordingly]

Spring (April–June 2022) streamflow was ranked much below normal in Arizona, Hawaii, Nevada, New Mexico, Texas, and Utah (fig. 7). Streamflow was ranked below normal in California, Colorado, Massachusetts, New Hampshire, North Carolina, Puerto Rico and the Virgin Islands, Rhode Island, and Vermont. Streamflow was ranked above normal in Arkansas, Michigan, and Missouri. Streamflow was ranked much above normal in Minnesota and North Dakota. Nationwide, spring-season streamflow ranked the 53d highest out of 93 years.

Figure 7. Spring (April–June 2022) statewide streamflow ranks in the United States compared to spring streamflows for water years 1930–2022.[Some colors in the explanation may not be used on the map; **, for Puerto Rico and the Virgin Islands, 79 years of available data were used and the rank was adjusted accordingly]

Summer (July–September 2022) streamflow was ranked much below normal in California and Hawaii (fig. 8). Streamflow was ranked below normal in Colorado, Connecticut, Massachusetts, Nebraska, Nevada, New Jersey, North Carolina, Oklahoma, and Rhode Island. Streamflow was ranked above normal in Arizona, District of Columbia, Illinois, Kentucky, Louisiana, and West Virginia. Streamflow was ranked much above normal in New Mexico, Mississippi, and Puerto Rico and the Virgin Islands. Nationwide, summer-season streamflow ranked the 67th highest out of 93 years.

Figure 8. Summer (July–September 2022) statewide streamflow ranks in the United States compared to summer streamflows for water years 1930–2022.[Some colors in the explanation may not be used on the map; **, for Puerto Rico and the Virgin Islands, 79 years of available data were used and the rank was adjusted accordingly]

Assuming individual streamgage data are independent of other streamgage data and are normally distributed, the monthly streamflow is expected to be high (greater than the 95th percentile) at 5 percent of the streamgages and is expected to be low (less than the 5th percentile) at 5 percent of the streamgages during any given month. The percentages of streamgages reporting high streamflow only in 1 month of water year 2022 (October 2021) were greater than or equal to the expected percentages (7 percent; fig. 9). In contrast, there were five months (February, March, April, May, and August 2022) with a greater-than-or-equal-to expected percentage of streamgages reporting low streamflow (6, 6, 5, 5, and 5 percent, respectively).

Figure 9. Percentage of streamgages with high and low monthly streamflow, October 1999– September 2022.