Evaluation and Adjustment of Historical Hydroclimate Data: Improving the Representation of Current Hydroclimatic Conditions in Key California Watersheds

The assumption of stationarity in historical hydroclimatic data, fundamental to traditional water resource planning models, is increasingly challenged by the impacts of climate change. This discrepancy can lead to inaccurate model outputs and misinformed management decisions. This study addresses th...

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Main Authors: Andrew Schwarz, Z. Q. Richard Chen, Alejandro Perez, Minxue He
Format: Article
Language:English
Published: MDPI AG 2025-01-01
Series:Hydrology
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Online Access:https://www.mdpi.com/2306-5338/12/2/22
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author Andrew Schwarz
Z. Q. Richard Chen
Alejandro Perez
Minxue He
author_facet Andrew Schwarz
Z. Q. Richard Chen
Alejandro Perez
Minxue He
author_sort Andrew Schwarz
collection DOAJ
description The assumption of stationarity in historical hydroclimatic data, fundamental to traditional water resource planning models, is increasingly challenged by the impacts of climate change. This discrepancy can lead to inaccurate model outputs and misinformed management decisions. This study addresses this challenge by developing a novel monthly data adjustment approach, the Runoff Curve Year–Type–Monthly (RC-YTM) method. The application of this method is exemplified at five key California watersheds. The RC-YTM method accounts for the increasing variability and shifts in seasonal runoff timing observed in the historical data (1922–2021), aligning it with the contemporary climate conditions represented by the period from 1992 to 2021 at the study watersheds. This method adjusts both annual and monthly streamflow values using a combination of precipitation–runoff relationships, quantile mapping, and water year classification. The adjusted data, reflecting current climatic conditions more accurately than the raw historical data, serve as valuable inputs for operational water resource planning models like CalSim3, commonly used in California for water management. This approach, demonstrably effective in capturing the observed climate change impacts on streamflow at monthly timesteps, enhances the reliability of model simulations representing contemporary conditions, which can lead to better-informed decision-making in water management, infrastructure investment, drought and flood risk assessment, and adaptation strategies. While focused on specific California watersheds, this study’s findings and the adaptable RC-YTM method hold significant implications for water resource management in other regions facing similar hydroclimatic challenges in a changing climate.
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spelling doaj-art-2e58cca4a9ad462ea7367181a4ac4fc82025-08-20T02:44:39ZengMDPI AGHydrology2306-53382025-01-011222210.3390/hydrology12020022Evaluation and Adjustment of Historical Hydroclimate Data: Improving the Representation of Current Hydroclimatic Conditions in Key California WatershedsAndrew Schwarz0Z. Q. Richard Chen1Alejandro Perez2Minxue He3California Department of Water Resources, Sacramento, CA 95814, USACalifornia Department of Water Resources, Sacramento, CA 95814, USACalifornia Department of Water Resources, Sacramento, CA 95814, USACalifornia Department of Water Resources, Sacramento, CA 95814, USAThe assumption of stationarity in historical hydroclimatic data, fundamental to traditional water resource planning models, is increasingly challenged by the impacts of climate change. This discrepancy can lead to inaccurate model outputs and misinformed management decisions. This study addresses this challenge by developing a novel monthly data adjustment approach, the Runoff Curve Year–Type–Monthly (RC-YTM) method. The application of this method is exemplified at five key California watersheds. The RC-YTM method accounts for the increasing variability and shifts in seasonal runoff timing observed in the historical data (1922–2021), aligning it with the contemporary climate conditions represented by the period from 1992 to 2021 at the study watersheds. This method adjusts both annual and monthly streamflow values using a combination of precipitation–runoff relationships, quantile mapping, and water year classification. The adjusted data, reflecting current climatic conditions more accurately than the raw historical data, serve as valuable inputs for operational water resource planning models like CalSim3, commonly used in California for water management. This approach, demonstrably effective in capturing the observed climate change impacts on streamflow at monthly timesteps, enhances the reliability of model simulations representing contemporary conditions, which can lead to better-informed decision-making in water management, infrastructure investment, drought and flood risk assessment, and adaptation strategies. While focused on specific California watersheds, this study’s findings and the adaptable RC-YTM method hold significant implications for water resource management in other regions facing similar hydroclimatic challenges in a changing climate.https://www.mdpi.com/2306-5338/12/2/22hydroclimatic stationarityclimate changedata adjustmentrunoff curveCalifornia
spellingShingle Andrew Schwarz
Z. Q. Richard Chen
Alejandro Perez
Minxue He
Evaluation and Adjustment of Historical Hydroclimate Data: Improving the Representation of Current Hydroclimatic Conditions in Key California Watersheds
Hydrology
hydroclimatic stationarity
climate change
data adjustment
runoff curve
California
title Evaluation and Adjustment of Historical Hydroclimate Data: Improving the Representation of Current Hydroclimatic Conditions in Key California Watersheds
title_full Evaluation and Adjustment of Historical Hydroclimate Data: Improving the Representation of Current Hydroclimatic Conditions in Key California Watersheds
title_fullStr Evaluation and Adjustment of Historical Hydroclimate Data: Improving the Representation of Current Hydroclimatic Conditions in Key California Watersheds
title_full_unstemmed Evaluation and Adjustment of Historical Hydroclimate Data: Improving the Representation of Current Hydroclimatic Conditions in Key California Watersheds
title_short Evaluation and Adjustment of Historical Hydroclimate Data: Improving the Representation of Current Hydroclimatic Conditions in Key California Watersheds
title_sort evaluation and adjustment of historical hydroclimate data improving the representation of current hydroclimatic conditions in key california watersheds
topic hydroclimatic stationarity
climate change
data adjustment
runoff curve
California
url https://www.mdpi.com/2306-5338/12/2/22
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AT zqrichardchen evaluationandadjustmentofhistoricalhydroclimatedataimprovingtherepresentationofcurrenthydroclimaticconditionsinkeycaliforniawatersheds
AT alejandroperez evaluationandadjustmentofhistoricalhydroclimatedataimprovingtherepresentationofcurrenthydroclimaticconditionsinkeycaliforniawatersheds
AT minxuehe evaluationandadjustmentofhistoricalhydroclimatedataimprovingtherepresentationofcurrenthydroclimaticconditionsinkeycaliforniawatersheds