Calibration Approaches for Distributed Hydrologic Models in Poorly Gaged Basins : Implication for Streamflow Projections under Climate Change

This study tests the performance and uncertainty of calibration strategies for a spatially distributed hydrologic model in order to improve model simulation accuracy and understand prediction uncertainty at interior ungaged sites of a sparsely gaged watershed. The study is conducted using a distribu...

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Main Authors:	Wi, S., Yang, Y. C. E., Steinschneider, S., Khalil, A., Brown, C. M.
Format:	Journal Article
Language:	en_US
Published:	European Geosciences Union 2015
Subjects:	streamflow water basin
Online Access:	http://hdl.handle.net/10986/23174

id	okr-10986-23174
recordtype	oai_dc
spelling	okr-10986-231742021-04-23T14:04:13Z Calibration Approaches for Distributed Hydrologic Models in Poorly Gaged Basins : Implication for Streamflow Projections under Climate Change Wi, S. Yang, Y. C. E. Steinschneider, S. Khalil, A. Brown, C. M. streamflow water basin This study tests the performance and uncertainty of calibration strategies for a spatially distributed hydrologic model in order to improve model simulation accuracy and understand prediction uncertainty at interior ungaged sites of a sparsely gaged watershed. The study is conducted using a distributed version of the HYMOD hydrologic model (HYMOD_DS) applied to the Kabul River basin. Several calibration experiments are conducted to understand the benefits and costs associated with different calibration choices, including (1) whether multisite gaged data should be used simultaneously or in a stepwise manner during model fitting, (2) the effects of increasing parameter complexity, and (3) the potential to estimate interior watershed flows using only gaged data at the basin outlet. The implications of the different calibration strategies are considered in the context of hydrologic projections under climate change. To address the research questions, high-performance computing is utilized to manage the computational burden that results from high-dimensional optimization problems. Several interesting results emerge from the study. The simultaneous use of multisite data is shown to improve the calibration over a stepwise approach, and both multisite approaches far exceed a calibration based on only the basin outlet. The basin outlet calibration can lead to projections of mid-21st century streamflow that deviate substantially from projections under multisite calibration strategies, supporting the use of caution when using distributed models in data-scarce regions for climate change impact assessments. Surprisingly, increased parameter complexity does not substantially increase the uncertainty in streamflow projections, even though parameter equifinality does emerge. The results suggest that increased (excessive) parameter complexity does not always lead to increased predictive uncertainty if structural uncertainties are present. The largest uncertainty in future streamflow results from variations in projected climate between climate models, which substantially outweighs the calibration uncertainty. 2015-12-01T19:50:44Z 2015-12-01T19:50:44Z 2015-02-10 Journal Article Hydrology and Earth System Sciences http://hdl.handle.net/10986/23174 en_US CC BY 3.0 IGO http://creativecommons.org/licenses/by/3.0/igo/ World Bank European Geosciences Union Publications & Research :: Journal Article Publications & Research Afghanistan
repository_type	Digital Repository
institution_category	Foreign Institution
institution	Digital Repositories
building	World Bank Open Knowledge Repository
collection	World Bank
language	en_US
topic	streamflow water basin
spellingShingle	streamflow water basin Wi, S. Yang, Y. C. E. Steinschneider, S. Khalil, A. Brown, C. M. Calibration Approaches for Distributed Hydrologic Models in Poorly Gaged Basins : Implication for Streamflow Projections under Climate Change
geographic_facet	Afghanistan
description	This study tests the performance and uncertainty of calibration strategies for a spatially distributed hydrologic model in order to improve model simulation accuracy and understand prediction uncertainty at interior ungaged sites of a sparsely gaged watershed. The study is conducted using a distributed version of the HYMOD hydrologic model (HYMOD_DS) applied to the Kabul River basin. Several calibration experiments are conducted to understand the benefits and costs associated with different calibration choices, including (1) whether multisite gaged data should be used simultaneously or in a stepwise manner during model fitting, (2) the effects of increasing parameter complexity, and (3) the potential to estimate interior watershed flows using only gaged data at the basin outlet. The implications of the different calibration strategies are considered in the context of hydrologic projections under climate change. To address the research questions, high-performance computing is utilized to manage the computational burden that results from high-dimensional optimization problems. Several interesting results emerge from the study. The simultaneous use of multisite data is shown to improve the calibration over a stepwise approach, and both multisite approaches far exceed a calibration based on only the basin outlet. The basin outlet calibration can lead to projections of mid-21st century streamflow that deviate substantially from projections under multisite calibration strategies, supporting the use of caution when using distributed models in data-scarce regions for climate change impact assessments. Surprisingly, increased parameter complexity does not substantially increase the uncertainty in streamflow projections, even though parameter equifinality does emerge. The results suggest that increased (excessive) parameter complexity does not always lead to increased predictive uncertainty if structural uncertainties are present. The largest uncertainty in future streamflow results from variations in projected climate between climate models, which substantially outweighs the calibration uncertainty.
format	Journal Article
author	Wi, S. Yang, Y. C. E. Steinschneider, S. Khalil, A. Brown, C. M.
author_facet	Wi, S. Yang, Y. C. E. Steinschneider, S. Khalil, A. Brown, C. M.
author_sort	Wi, S.
title	Calibration Approaches for Distributed Hydrologic Models in Poorly Gaged Basins : Implication for Streamflow Projections under Climate Change
title_short	Calibration Approaches for Distributed Hydrologic Models in Poorly Gaged Basins : Implication for Streamflow Projections under Climate Change
title_full	Calibration Approaches for Distributed Hydrologic Models in Poorly Gaged Basins : Implication for Streamflow Projections under Climate Change
title_fullStr	Calibration Approaches for Distributed Hydrologic Models in Poorly Gaged Basins : Implication for Streamflow Projections under Climate Change
title_full_unstemmed	Calibration Approaches for Distributed Hydrologic Models in Poorly Gaged Basins : Implication for Streamflow Projections under Climate Change
title_sort	calibration approaches for distributed hydrologic models in poorly gaged basins : implication for streamflow projections under climate change
publisher	European Geosciences Union
publishDate	2015
url	http://hdl.handle.net/10986/23174
_version_	1764453112599281664

Calibration Approaches for Distributed Hydrologic Models in Poorly Gaged Basins : Implication for Streamflow Projections under Climate Change

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