Reservoirs created by impounding sediment-laden streams infill over time, reducing storage capacity and altering water quality. Increasing freshwater demand on a limited supply is adding pressure on reservoir water storage and management across much of the western and central U.S. Determining sedimentation rates is helpful to ensure a reliable and sustainable clean water supply for drinking, irrigation and recreation purposes. In the state of Kansas, located in the central Great Plains, bathymetric surveys have been completed recently for many major state and federally constructed reservoirs. In this paper, we examine sediment infill rate and storage capacity loss for all 24 federally operated reservoirs in Kansas. As of 2016, these reservoirs have an average age of 52 years and collectively have lost approximately 17% of their original capacity, with the highest single-reservoir loss of 45%, the highest annual loss rate of 0.84%, and the highest annual sediment yield of 1688 m³/km²/year. Results from this paper provide baseline information pertinent to the development, prioritization and assessment of remediation and mitigation strategies for addressing the sediment infill problem in Kansas, with general implications for other large reservoirs across the Great Plains as well as other climatologically and ecologically similar regions around the world.

Precipitation directly impacts agricultural production, water resources management, and recreational activities, all of which significantly affect a state's economy. As the human population increases, demand for water escalates due to its crucial role in human health and food production. The question then becomes, can current water management strategies ensure sustainable access to clean water, maintain food supplies, and permit industrial uses given a changing climate? Developing a solid understanding of rainfall patterns and trends is vital, particularly for regions like Kansas with high spatial and temporal climate variability. In this study, three statistical methods were used to analyse annual rainfall trends in Kansas using daily rainfall data from 1890 through 2011: (1) a linear regression model, (2) the Mann‐Kendall test, and (3) the Spearman test. A gradual increase in total annual rainfall was noted for 21 of 23 stations, including eight statistically significant upward trends. The 23 station period of record average slope for Kansas was 6.8 mm per 10 year with a minimum value of −8.5 mm per 10 year for Saint Francis in the northwest and a maximum value of 20.1 mm per 10 year for Independence in the southeast. In addition, sudden change analyses were conducted using cumulative sum and Pettitt tests. At 12 stations, significant change‐points were detected as early as 1940 and as recently as 1980. The increasing trend, particularly after the significant change‐points, is useful in updating water management plans. Total annual rainfall correlates with available water in soil, lakes, streams, and reservoirs and can assist with agricultural production decisions such as crop selection and new plant variety development when combined with rainfall distribution analysis throughout the year.

Climate variability and change can impact rainfall by varying time, location, magnitude, and frequency of precipitation events. Fluctuations in heavy rainfall events can impact flooding and drought events and water management systems. This research addresses temporal and spatial distributions of extreme daily and monthly rainfall in Kansas using daily rainfall data from 23 stations for the period 1890–2013. The Mann–Kendall non‐parametric method was used in trend analysis. Results indicate an increasing trend in the annual daily maximum rainfall, and an increase in the annual number of rainfall events above the 90th, 95th, and 99th percentile thresholds at a majority of stations since 1890. The most recent 30‐year climate normal period (1981–2010) was selected to assess contemporary change compared to the entire period (1890–2013). Most stations have a steeper positive slope for all extreme rainfall parameters for 1981–2010. Generally, western Kansas receives smaller and fewer extreme storms than eastern Kansas with respect to both magnitude and frequency.Since 1890, June has been the month that receives the greatest amount of rain in each year at a majority of stations (18 of 23). Stations in eastern Kansas tend to experience earlier maximum rainfall on a monthly basis than central and western stations. Earlier annual maximum monthly rains can affect soil moisture and runoff generation. Timely maintenance and improvement in water, soil, and flood management systems are necessary in order to increase preparedness of the society to flash floods and protect them from water management systems failures.