Abstract
A new daily water balance model is developed and tested in this paper. The new model has a similar model structure to the existing probability distributed rainfall runoff models (PDM), such as HyMOD. However, the model utilizes a new distribution function for soil water storage capacity, which leads to the SCS (Soil Conservation Service) curve number (CN) method when the initial soil water storage is set to zero. Therefore, the developed model is a unification of the PDM and CN methods and is called the PDM–CN model in this paper. Besides runoff modeling, the calculation of daily evaporation in the model is also dependent on the distribution function, since the spatial variability of soil water storage affects the catchment-scale evaporation. The generated runoff is partitioned into direct runoff and groundwater recharge, which are then routed through quick and slow storage tanks, respectively. Total discharge is the summation of quick flow from the quick storage tank and base flow from the slow storage tank. The new model with 5 parameters is applied to 92 catchments for simulating daily streamflow and evaporation and compared with AWMB, SACRAMENTO, and SIMHYD models. The performance of the model is slightly better than HyMOD but is not better compared with the 14-parameter model (SACRAMENTO) in the calibration, and does not perform as well in the validation period as the 7-parameter model (SIMHYD) in some areas, based on the NSE values. The linkage between the PDM–CN model and long-term water balance model is also presented, and a two-parameter mean annual water balance equation is derived from the proposed PDM–CN model.
Highlights
Conceptual water balance models have been used to simulate and predict hydrological variables for many applications, such as reservoir operations and climate change impact assessments
The linkage between the probability distributed rainfall runoff models (PDM)–curve number (CN) model and long-term water balance model is presented, and a two-parameter mean annual water balance equation is derived from the proposed PDM–CN model
The objective of this paper is to develop a daily water balance model, based on the new distribution function for soil water storage capacity
Summary
Conceptual water balance models have been used to simulate and predict hydrological variables (e.g., runoff, evaporation, and storage change) for many applications, such as reservoir operations and climate change impact assessments. As an example, have depicted poor simulations for minimum flow situations; in that respect, the representation of hydrological process will depend on how relevant models are developed to meet low-flow conditions [2,3] Conceptual models have their advantages and disadvantages. They can predict and simulate hydrological processes for decision making [4,5,6,7,8], prediction of streamflow in ungauged watersheds [9,10,11,12,13], evaluating changes of land use [14,15,16,17], evaluating climate change implications [18,19,20,21], and evaluating human impacts [4,22,23]. Hydrological models can have limitations in considering groundwater exchange, in oversimplifying hydrological processes, or in their
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
