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ARS Home » Plains Area » El Reno, Oklahoma » Grazinglands Research Laboratory » Agroclimate and Natural Resources Research » Research » Publications at this Location » Publication #329890

Research Project: AGRICULTURAL LAND MANAGEMENT TO OPTIMIZE PRODUCTIVITY AND NATURAL RESOURCE CONSERVATION AT FARM AND WATERSHED SCALES

Location: Agroclimate and Natural Resources Research

Title: Annual baseflow variations as influenced by climate variability and agricultural land use change in the Missouri River basin

Author
item Ahiablame, Laurent - South Dakota State University
item Sheshukov, Aleksey - Kansas State University
item Rahmani, Vahid - Kansas State University
item Moriasi, Daniel

Submitted to: Journal of Hydrology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/26/2017
Publication Date: 5/31/2017
Citation: Ahiablame, L., Sheshukov, A.Y., Rahmani, V., Moriasi, D.N. 2017. Annual baseflow variations as influenced by climate variability and agricultural land use change in the Missouri River basin. Journal of Hydrology. 188-202.

Interpretive Summary: Knowing variations in long-term water flow data is essential in planning for and managing water resources effectively. Trends in baseflow and precipitation in the Missouri River Basin (MORB) were evaluated. Effects of precipitation and agricultural land use on baseflow were also evaluated. Long-term baseflow data (65 years) were derived from daily streamflow records separating baseflow and surface runoff proportions at 99 stream gauge stations in the MORB. Results showed that average annual baseflow varied between 0.08 and 330 mm across the MORB. Baseflow index, defined as the proportion of baseflow in total streamflow, ranged from 0.38 to 0.80 with an average of 0.60, suggesting that 60% of long-term streamflow in MORB is likely supported by subsurface water. While there were no noticeable spatial patterns for trends in baseflow and precipitation across the basin, annual baseflow trend results revealed increasing trends for 73 stations while 26 stations showed decreasing trends. Trend analysis on annual precipitation showed that 78 stations had upward trends and 21 downward trends. The results also showed that for a 1% increase in precipitation, baseflow increased with a magnitude of 1 to 4% in 97 gauge stations. Annual baseflow in two stations slightly decreased (0-0.2%) for a 1% increase in precipitation. The study analyses also showed that a 1 % increase in agricultural land use resulted in a 0.2% decrease in baseflow within the MORB. While the observed trends of baseflow and its relationships with variability of precipitation and agricultural land use are entirely dependent on the quality of data used in this study, they provide useful insight into the influence of climate and land use change on environmental flows in the northern Great Plains region.

Technical Abstract: Detection of changes (steady or abrupt) in long time series of hydrological data is important for effective planning and management of water resources. This study evaluated trends in baseflow and precipitation in the Missouri River Basin (MORB) using a modified Mann-Kendall (MK) test. Precipitation and agricultural land use elasticities of baseflow were also evaluated with a non-parametric estimator of elasticity. Long-term baseflow data (1950-2014) were derived from daily streamflow records with a recursive digital filter method for baseflow separation for 99 streams in the Missouri River Basin. Results showed that digitally filtered average annual baseflow varies between 0.08 and 330 mm across the MORB. Baseflow index (BFI) defined as the proportion of baseflow in total streamflow ranges from 0.38 to 0.80 with an average of 0.60, suggesting that 60% of long-term streamflow in MORB is likely supported by subsurface water. While there are no noticeable spatial patterns for trends in baseflow and precipitation across the basin, annual baseflow trend results revealed upward trends for 73 stations of which 40 stations had statistically significant positive trends; 26 stations showed downward trends with 7 having statistically significant negative trends. Trend analysis on annual precipitation showed that 78 stations (28 statistically significant) had upward trends and 21 (5 statistically significant) downward trends. The elasticity analysis showed baseflow increase with a magnitude of 1 to 4% in 97 gauge stations (with 27 statistically significant) out of 99 for a 1% increase in precipitation. Annual baseflow in two stations slightly decreased (0-0.2%) for a 1% increase in precipitation. Land use elasticity of baseflow revealed that a 1 % increase of agricultural land use would result in a 0.2% decrease in baseflow within the MORB. While the observed trends and elasticities of baseflow are entirely dependent on the quality of data used in this study, they provide useful insight into the influence of climate and land use change on environmental flows in the northern Great Plains region.