A novel approach to recognize the long-term spatial-temporal pattern of dry and wet years over Iran

Modabber-Azizi, Sajjad; Salarijazi, Meysam; Ghorbani, Khalil

doi:10.1016/j.pce.2023.103426

Cited by 6 publications

(1 citation statement)

References 58 publications

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“…Moreover, the influence of climate change further compounds the impact on the seasonal patterns, thereby affecting the overall seasonality of streamflow discharge [31]. It is crucial to recognize that the non-stationarity of hydro-meteorological variables, induced by climate change, has significant implications for both annual and seasonal patterns [32][33][34].…”

Section: Additional Factors In the Swe-sfda Relationshipmentioning

confidence: 99%

An Imputing Technique for Surface Water Extent Timeseries with Streamflow Discharges

Yin,

Peña

2024

Water

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A continuous and multi-decadal surface water extent (SWE) record is vital for water resources management, flood risk assessment, and comprehensive climate change impact studies. The advancements in remote sensing technologies offer a valuable tool for monitoring surface water with high temporal and spatial resolution. However, challenges persist due to image gaps resulting from sensor issues and adverse weather conditions during data collection. To address this issue, one way to fill the gaps is by leveraging in situ measurements such as streamflow discharges (SFDs). We investigate the relationship between SFDs and Landsat-derived SWE in the New England region watersheds (eight-digit hydrological unit code (HUC)) on a monthly scale. While previous studies indicate the relationship exists, it remains elusive for larger domains. Recent research suggests using monthly average SFD data from a single stream gage to fill the gaps in SWE. However, as SWE represents a monthly maximum value, relying on a single gage with average values may not capture the complex dynamics of surface water. Our study introduces a novel approach by replacing the monthly average SFD with the maximum day streamflow discharge anomaly (SFDA) within a month. This adjustment aims to better reflect extreme scenarios, and we explore the relationship using ridge regression, incorporating data from all stream gages in the study domain. The SWE and SFDA are both transformed to stabilize the variance. We found that there is no discernible correlation between the magnitude of the correlation and the size of the basins. The correlations vary based on HUC and display a wide range, indicating the variances of the importance of stream gages to each HUC. The maximum correlation is found when the stream gage is located outside of the target HUC, further verifying the complex relationship between SWE and SFDA. Covering over 30 years of data across 45 HUCs, the imputing technique using ridge regression shows satisfactory performance for most of the HUCs analyzed. The results show that 41 out of 45 HUCs achieve a root-mean-square error (RMSE) of less than 10, and 44 out of 45 HUCs exhibit a normalized root-mean-square error (NRMSE) of less than 0.1. Of 45 HUCs, 42 have an R-squared (R2) score higher than 0.7. The Nash–Sutcliffe efficiency index (Ef) shows consistent results with R2, with the relative bias ranging from –0.02 to 0.03. The established relationship serves as an effective imputing technique, filling gaps in the time series of SWE. Moreover, our approach facilitates the identification and visualization of the most significant gages for each HUC, contributing to a more refined understanding of surface water dynamics.

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Section: Additional Factors In the Swe-sfda Relationshipmentioning

confidence: 99%

An Imputing Technique for Surface Water Extent Timeseries with Streamflow Discharges

Yin,

Peña

2024

Water

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Effect of dam construction on changes in river's environmental flow (case study: Gorganrood river in the south of the Caspian Sea)

Zargari,

Salarijazi,

Ghorbani

et al. 2023

Appl Water Sci

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Human activities such as dam construction can lead to significant river flow regime changes and, consequently, river environments and habitats. Different approaches for estimating the environmental flow have developed to improve the river ecosystem's environmental and habitat conditions. The hydrological approach is considered in many studies to estimate environmental flows considering its advantages. Vimba vimba persa is an economically and ecologically valuable species in the Caspian Sea that spawns and reproduces naturally in the Gorganrood River downstream in April–May. After the construction of the Voshmgir dam on the Gorganrood River, the fish population has drastically reduced in recent decades. In this study, to investigate the effect of constructing the Voshmgir dam on the environmental flow of Gorganrood River, a wide range of hydrological methods, including Tennant, Tessman, Arkansas, Aquatic Base Flow, Flow Duration Curve, High Flow-Low Flow, and FDC Shifting have been used. Comparing the correlation between the mean monthly flow time series before and after the Voshmgir dam demonstrates remarkable changes, including Pearson (0.95 to 0.86), Spearman's rho (0.93 to 0.78), and Kendall's τ (0.78 to 0.61) as a consequence of dam construction. The results indicate that estimated environmental flow from Tennant (1.1, 3.4 to 1.3, 3.8 cms) and Aquatic Base Flow (0.5 to 1.8 cms) methods have led to inadequate estimation due to significant changes in flow in different months. The amount of environmental flow during April–May estimated from investigated methods indicates the dam negatively affected water allocation to meet the river downstream's ecological and environmental needs. The flow duration curve analysis confirms that the dam construction has caused the river flow to fluctuate significantly within the year. The dam construction has dramatically reduced the flow in April–May, a critical environmental and ecological season. The April–May period coincides with the river's flood season. The construction of the Voshmgir dam has caused the components of high flow in the environmental flow to face severe shortages.

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Evaluation of the Usability of the Rainfall Anomaly Index (RAI) Instead of the Standard Precipitation Index (SPI)

Aydin

2024

Iran J Sci Technol Trans Civ Eng

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A novel approach to recognize the long-term spatial-temporal pattern of dry and wet years over Iran

Cited by 6 publications

References 58 publications

An Imputing Technique for Surface Water Extent Timeseries with Streamflow Discharges

An Imputing Technique for Surface Water Extent Timeseries with Streamflow Discharges

Effect of dam construction on changes in river's environmental flow (case study: Gorganrood river in the south of the Caspian Sea)

Evaluation of the Usability of the Rainfall Anomaly Index (RAI) Instead of the Standard Precipitation Index (SPI)

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