Spectral Analysis of Hydrological Signals to Estimate Watershed Properties Considering Impacts of Unsaturated Zone
Abstract Understanding responses of stream discharge to precipitation in a watershed is important in gaining insights into watershed hydrology and estimating hydraulic parameters. Transfer functions in the spectral domain are commonly used to quantify the relationship between precipitation and disch...
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| Format: | Article |
| Language: | English |
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Wiley
2024-11-01
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| Series: | Water Resources Research |
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| Online Access: | https://doi.org/10.1029/2023WR036680 |
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| _version_ | 1849227282234736640 |
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| author | Yunqiu Zhou Xiuyu Liang Enze Ma Kewei Chen Keith Schilling Tianyuan Zheng Yuhu Zheng You‐Kuan Zhang Chunmiao Zheng |
| author_facet | Yunqiu Zhou Xiuyu Liang Enze Ma Kewei Chen Keith Schilling Tianyuan Zheng Yuhu Zheng You‐Kuan Zhang Chunmiao Zheng |
| author_sort | Yunqiu Zhou |
| collection | DOAJ |
| description | Abstract Understanding responses of stream discharge to precipitation in a watershed is important in gaining insights into watershed hydrology and estimating hydraulic parameters. Transfer functions in the spectral domain are commonly used to quantify the relationship between precipitation and discharge, and estimate watershed hydraulic parameters. However, previous models have not adequately accounted for the impact of the unsaturated zone. To address this, we have developed a novel analytical model that considers the effect of the unsaturated zone to obtain transfer functions within watersheds. These transfer functions are derived by the spectral method and verified through numerical simulations. The results indicate that the transfer functions are influenced significantly by the relative hydraulic conductivity exponent αk in the moisture characteristic curve. A higher αk results in a lower transfer function, indicating more robust filtering of hydrological signals. A thicker unsaturated zone results in lower transfer functions at higher frequencies. The traditional transfer functions, which neglect the retention capacity of the unsaturated zone, tend to overestimate hydrological responses at high frequencies. Our transfer functions agree well with integrated watershed‐scale flow models and are also applied to observed data from four watersheds in Iowa, providing reasonable estimates for the hydraulic parameters. This study contributes to a deeper understanding of watershed behavior and offers an enhanced tool for estimating hydraulic parameters with practical applications. |
| format | Article |
| id | doaj-art-3c278823a8df44f3a46a48628e9bde7e |
| institution | Kabale University |
| issn | 0043-1397 1944-7973 |
| language | English |
| publishDate | 2024-11-01 |
| publisher | Wiley |
| record_format | Article |
| series | Water Resources Research |
| spelling | doaj-art-3c278823a8df44f3a46a48628e9bde7e2025-08-23T13:05:51ZengWileyWater Resources Research0043-13971944-79732024-11-016011n/an/a10.1029/2023WR036680Spectral Analysis of Hydrological Signals to Estimate Watershed Properties Considering Impacts of Unsaturated ZoneYunqiu Zhou0Xiuyu Liang1Enze Ma2Kewei Chen3Keith Schilling4Tianyuan Zheng5Yuhu Zheng6You‐Kuan Zhang7Chunmiao Zheng8School of Environmental Science and Engineering Southern University of Science and Technology Shenzhen ChinaSchool of Environmental Science and Engineering Southern University of Science and Technology Shenzhen ChinaSchool of Environmental Science and Engineering Southern University of Science and Technology Shenzhen ChinaSchool of Environmental Science and Engineering Southern University of Science and Technology Shenzhen ChinaDepartment of Earth and Environmental Sciences University of Iowa Iowa City IA USACollege of Environmental Science and Engineering Ocean University of China Qingdao ChinaAcademy of Environmental Planning & Design, Co., Ltd. Nanjing University Nanjing ChinaSchool of Environmental Science and Engineering Southern University of Science and Technology Shenzhen ChinaSchool of Environmental Science and Engineering Southern University of Science and Technology Shenzhen ChinaAbstract Understanding responses of stream discharge to precipitation in a watershed is important in gaining insights into watershed hydrology and estimating hydraulic parameters. Transfer functions in the spectral domain are commonly used to quantify the relationship between precipitation and discharge, and estimate watershed hydraulic parameters. However, previous models have not adequately accounted for the impact of the unsaturated zone. To address this, we have developed a novel analytical model that considers the effect of the unsaturated zone to obtain transfer functions within watersheds. These transfer functions are derived by the spectral method and verified through numerical simulations. The results indicate that the transfer functions are influenced significantly by the relative hydraulic conductivity exponent αk in the moisture characteristic curve. A higher αk results in a lower transfer function, indicating more robust filtering of hydrological signals. A thicker unsaturated zone results in lower transfer functions at higher frequencies. The traditional transfer functions, which neglect the retention capacity of the unsaturated zone, tend to overestimate hydrological responses at high frequencies. Our transfer functions agree well with integrated watershed‐scale flow models and are also applied to observed data from four watersheds in Iowa, providing reasonable estimates for the hydraulic parameters. This study contributes to a deeper understanding of watershed behavior and offers an enhanced tool for estimating hydraulic parameters with practical applications.https://doi.org/10.1029/2023WR036680transfer functionunsaturated zonespectral analysisanalytical solution |
| spellingShingle | Yunqiu Zhou Xiuyu Liang Enze Ma Kewei Chen Keith Schilling Tianyuan Zheng Yuhu Zheng You‐Kuan Zhang Chunmiao Zheng Spectral Analysis of Hydrological Signals to Estimate Watershed Properties Considering Impacts of Unsaturated Zone Water Resources Research transfer function unsaturated zone spectral analysis analytical solution |
| title | Spectral Analysis of Hydrological Signals to Estimate Watershed Properties Considering Impacts of Unsaturated Zone |
| title_full | Spectral Analysis of Hydrological Signals to Estimate Watershed Properties Considering Impacts of Unsaturated Zone |
| title_fullStr | Spectral Analysis of Hydrological Signals to Estimate Watershed Properties Considering Impacts of Unsaturated Zone |
| title_full_unstemmed | Spectral Analysis of Hydrological Signals to Estimate Watershed Properties Considering Impacts of Unsaturated Zone |
| title_short | Spectral Analysis of Hydrological Signals to Estimate Watershed Properties Considering Impacts of Unsaturated Zone |
| title_sort | spectral analysis of hydrological signals to estimate watershed properties considering impacts of unsaturated zone |
| topic | transfer function unsaturated zone spectral analysis analytical solution |
| url | https://doi.org/10.1029/2023WR036680 |
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