Streamflow Trends and Responses to Climate Variability and Land Cover Change in South Dakota

Karishma Kibria,Gemechis Djira,Laurent Ahiablame,Christopher Hay

doi:10.3390/hydrology3010002

Karishma Kibria, Gemechis Djira + Show 2 more

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https://doi.org/10.3390/hydrology3010002

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Abstract

Trends in high, moderate, and low streamflow conditions from United States Geological Survey (USGS) gauging stations were evaluated for a period of 1951–2013 for 18 selected watersheds in South Dakota (SD) using a modified Mann-Kendall test. Rainfall trends from 21 rainfall observation stations located within 20-km of the streamflow gauging stations were also evaluated for the same study period. The concept of elasticity was used to examine sensitivity of streamflow to variation in rainfall and land cover (i.e., grassland) in the study watersheds. Results indicated significant increasing trends in seven of the studied streams (of which five are in the east and two are located in the west), nine with slight increasing trends, and two with decreasing trends for annual streamflow. About half of the streams exhibited significant increasing trends in low and moderate flow conditions compared to high flow conditions. Ten rainfall stations showed slight increasing trends and seven showed decreasing trends for annual rainfall. Streamflow elasticity analysis revealed that streamflow was highly influenced by rainfall across the state (five of eastern streams and seven of western streams). Based on this analysis, a 10% increase in annual rainfall would result in 11%–30% increase in annual streamflow in more than 60% of SD streams. While streamflow appears to be more sensitive to rainfall across the state, high sensitivity of streamflow to rapid decrease in grassland area was detected in two western watersheds. This study provides valuable insight into of the relationship between streamflow, climate, and grassland cover in SD and would support further research and stakeholder decision making about water resources.

Highlights

South Dakota (SD) is located in the United States (US) Northern Great Plains region, which spansMontana, North Dakota, Wyoming, and Nebraska and is one of the largest prairie grasslands in the world [1]
The analysis indicates that 62% of the computed rainfall elasticity coefficients varied between 1.0 and 3.0, suggesting that a 1% annual rainfall increase would result in more than a 1% annual streamflow increase
Results fromout the of 12 western watersheds butthat wasannual not noticeable elastic to change in grassland areatrends in eastern watersheds

Summary

Introduction

South Dakota (SD) is located in the United States (US) Northern Great Plains region, which spans. North Dakota, Wyoming, and Nebraska (in addition to SD) and is one of the largest prairie grasslands in the world [1]. In 2011 alone, approximately 1800 km of grassland was converted to cropland for corn production in the state [3]. The economy in SD relies greatly on agricultural activities with the production of corn, soybean, and wheat as the state’s top commodity crops [4]. During the last few decades, corn and cattle are the two most important agricultural products, accounting for a little over one third of the total agricultural production of the state [4,5]. The Renewable Fuel Association ranked SD sixth in the US for corn

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