Figure: Colorado River Basin.

Quantifying impact of dams on streamflow characteristics

Dams meet various human needs such as hydropower generation, municipal water supply and flood control. However, dams alter the natural flow regime of rivers and adversely impact the river ecosystem. For example, dams hinder the downstream upstream movement of fish and trap the nutrient rich sediments. We examined how the human-induced flow alteration varies across the basin for the highly regulated Colorado River in the US. This methods developed will contribute to evaluate the operating policy of the reservoirs (dams) for a holistic management.

Related publications

  1. Hwang, J., Kumar, H., Ruhi, A., Sankarasubramanian, A., & Devineni, N. (2021). Quantifying Dam-Induced Fluctuations in Streamflow Frequencies Across the Colorado River Basin. Water Resources Research, https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2021WR029753.

  2. Kumar, H., Hwang, J., Devineni, N., Sankarasubramanian, A. (2022). Dynamic Flow Alteration Index for Complex River Networks With Cascading Reservoir Systems, Water Resources Research, https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2021WR030491.

  3. Ruhi, A., Hwang, J., Devineni, N., Mukhopadhyay, S., Kumar, H., Comte, L., Worland, S., Sankarasubramanian, A. (2022). How does flow alteration propagate across a large, highly regulated basin? Dam attributes, network context, and implications for biodiversity, Earth’s Future, https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2021EF002490

Related presentations

  1. Ruhi, A., Hwang, J., Devineni, N., Mukhopadhyay, S., Kumar, H., Comte, L., Worland, S., and Sankarasubramanian, A. (2019). How does flow alteration propagate across a large, highly regulated basin? Dam attributes, network context, and implications for biodiversity. In AGU Fall Meeting Abstracts, 2019, H23N 2086. (Poster presentation)

Figure: The conceptual model of deficit irrigation showing the value of crop yield under deficit irrigation (yellow lines) varies between yield under rainfed (blue line) and full irrigation (orange line).

Understanding the food-energy-water nexus through hydroeconomic modeling

Understanding the nexus between food, energy and water (FEW) systems is critical for basins with intensive agricultural water use as they face significant challenges under changing climate and regional development. We consider Flint River basin, GA, to understand the FEW nexus as agricultural water use accounts for a third of total water withdrawals. Potential changes in climate indicate drier summer months and increased competition between public utility and agricultural water use due to regional development. We investigate the nexus through a hydroeconomic modeling framework that considers groundwater pumping under various climate and deficit irrigation scenarios.

Related publications

  1. Kumar, H., Zhu, T., and Sankarasubramanian, A. (n.d.). Understanding the food-energy-water nexus through hydroeconomic modeling under regional development portfolios (Working paper)

Related presentations

  1. Kumar, H., Sankarasubramanian, A., and Zhu, T. (2022). Food-Water-Energy System: Challenges in Modeling and Quantifying the Nexus. In ICWRER 2022 (The 9th International Conference on Water Resources and Environment Research), University of Central Florida, Orlando, Florida, USA April 25-27, 2022. (Oral presentation - Accepted)

  2. Kumar, H., Zhu, T., and Sankarasubramanian, A. (2022). Modeling FEWS nexus through Regional Hydroeconomic Optimization (RHEO) framework. In INFEWS Synthesis PI Workshop 2022 (9-11 Feb 2022), Princeton University, New Jersey, USA. (Virtual oral presentation)

  3. Kumar, H., Sankarasubramanian, A., and Zhu, T. (2020). Understanding the food-energy-water nexus through hydroeconomic modeling under near-term climate change and regional development portfolios. In AGU Fall Meeting Abstracts, 2020, H143-0008. (Virtual poster presentation)

Figure: Drought conditions using proposed NJDI in September 1965. D0 represents no drought and D4 represents extremely dry conditions.

Non-stationary drought analysis

Droughts occur due to insufficient availability of water and have become more frequent under the changing climate. It is imperative to study droughts as they have serious socioeconomic implications. Drought indices are used to quantify the severity of meteorological droughts. For example, the value of Standardized Precipitation Index (SPI) less than -2 denotes extreme drought. However, most existing indices do not account for changing climate. We examined how can we update the drought indices to incorporate non-stationary in the precipitation. The proposed drought index is developed by coupling the Joint Deficit Index with the extended Time Sliding Window based Nonstationary Modeling. The proposed index has two main advantages: (i) it detects the signature of non-stationarity in the distribution parameter rather than the original time series, and (ii) it captures both long-term (i.e., trend) and short-term (i.e., step-change).

Related publications

  1. Vinnarasi, R., Dhanya, C.T., and Kumar, H. (2022). Tracing Time-varying Drought Characteristics through Nonstationary Joint Deficit Index. Journal of Climate, Under Review.

Related presentations

  1. Dhanya, C.T., Vinnarasi, R., Kumar, H. (2018). Copula-Based Non-Stationary Joint Deficit Index for Drought Characterization. In AGU Fall Meeting Abstracts, 2018, H51I-1417. (Poster presentation)