Research

Development of a Budyko-Based Snow Representation for Better Streamflow Predictions

(Left) Diagram of the hydrological partitioning process of the snow augmented ZDWBM (left) and the corresponding flowchart (right). / (Right) Comparison of NSE for the proposed model and original ZDWBM.

__We improved Zhang’s monthly water balance model (a physics-based conceptual hydrologic model) that reflects the physical partitioning process of the hydrological cycle at the basin level based on regional climate and catchment characteristics. The existing model does not include snow process and has confronted evident limitations in snow-affected areas, which is a critical aspect since snowmelt water has been a significant source of water resources for many regions, especially in the temperate and frigid zones. To this end, we introduce a snow module based on surface energy balance and Budyko-limits on melting and combine it with the existing water balance equations. Moreover, monthly parameterization is applied to the model to better explain the time-varying hydrological characteristics of a catchment.

Related Publication(s):

Hwang, J., & Devineni, N. (2022). An improved Zhang’s Dynamic Water Balance Model using Budyko‐based snow representation for better streamflow predictions. Water Resources Research, e2021WR030203.

Git Repository for ZDWBM-msnow: https://github.com/JHwangHydro/ZDWBM-msnow

Evaluation of the Local and Cumulative Impacts of Reservoirs on Streamflow Regimes

(Left) Spatial distribution of the 26 selected USGS streamflow gauging stations and 61 intermediate-to-large NID dams across the Colorado River Basin (including both Upper and Lower Colorado Basins). / (Right) Simplified diagram of the riverine network with the local and cumulative alterations measured for both the annual (a) and multi-annual frequency bands (b). Dam-induced local regulations are represented with triangles, and cumulative alterations are denoted with circles.

__Despite the positive services that the natural river provides, most inland waterways within the continental United States are now artificially altered by thousands of dams simultaneously distorting the magnitude and periodicity of the natural streamflow directly under various purposes. We examined the highly regulated Colorado River Basin to understand how flow alteration propagates over space regarding both magnitude and periodicity as influenced by dam operations. This analysis will contribute to a more objective evaluation of operating rules for reservoir systems.

Related Publication(s):

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, 57(10), e2021WR029753.

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, In press.