A 50-year analysis of hydrological trends and processes in a Mediterranean catchment

Folton, Nathalie; Martin, E.; Arnaud, Patrick; L'Hermite, P; Tolsa, Mathieu

doi:10.5194/hess-2018-547

Cited by 4 publications

(5 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Due to changes in precipitation and temperature, the scarcity of water resources may become more severe [18,19] and may greatly affect the hydrological system [20]. In response to change in climate, there is a marked tendency towards a decrease in the water resources and with a consistent increase in drought severity and duration [21]. Characterizing precipitation and flow trends is crucial for any design of sustainable water management strategies and to reduce the impact of droughts and floods [18,22,23].…”

Section: Introductionmentioning

confidence: 99%

Long-Term Homogeneity and Trends of Hydroclimatic Variables in Upper Awash River Basin, Ethiopia

Daba

Ayele

Suning

2020

Advances in Meteorology

View full text Add to dashboard Cite

Understanding long-term trends in hydroclimatic variables is important for future sustainable water resource management as it could show the possible regime shifts in hydrology. The main objective of this study was to analyze the homogeneity and trends of hydroclimatic data of Upper Awash Sab-Basin (UASB) in Oromia, Ethiopia, by employing homogeneity tests and Mann-Kendall and Sen’s slope tests. The data consist of 18 rainfall stations, 8 temperature stations, and 8 flow gauging stations across the UASB. Homogeneity and trends in streamflow, rainfall, and temperature variables were analyzed for the time period 1980 to 2017. In order to analyze homogeneity of hydroclimatic variables, we used four homogeneity tests (Pettitt’s test, Buishand’s test, standard normal homogeneity test, and von Neumann ratio test) at 5% significance level. Based on the outputs of four homogeneity tests, the results were classified into three categories, namely, “useful,” “doubtful,” and “suspect” to select the homogeneity stations. Mann-Kendall (Z) and Sen’s slope tests (Q) were applied for the selected homogeneous time series to detect the trend and magnitude of changes in hydroclimatic variables. The result showed that most of the stations in annual rainfall and streamflow data series were classified as useful. It is found that 58% of the rainfall stations were homogeneous. It is highlighted that 3 out of 8 discharge gauging stations have an inhomogeneity as they failed from one or a combination of the four tests. The MK revealed significant decreasing trends of annual rainfall in Addis Alem (Q = −19.81), Akaki (Q = −5.60), Hombole (Q = −9.49), and Ghinch (Q = −12.38) stations. The trend of annual temperature was a significant increasing trend in Addis Ababa Bole (Q = 0.05), Addis Ababa Tikur Ambessa (Q = 0.03), Tulu Bolo (Q = 0.07), and Addis Alem (Q = 0.06) stations. The results of discharge showed a significant increasing trend in Bega at Mojo (Q = 0.17) and Hombole (Q = 0.03) gauging stations. In general, the results obtained from discharge, rainfall, and temperature series indicated that most of the stations exhibited no trends in both annual and seasonal time series. It can be concluded that decreases in average annual rainfall totals and increases in mean annual temperature will probably drive sub-basin scale changes in discharge. We believe that the results obtained can fill information gaps on homogeneity and trends of hydroclimatic variables, which is very crucial for future water resource planning and management in the face of climate change.

show abstract

Section: Introductionmentioning

confidence: 99%

Long-Term Homogeneity and Trends of Hydroclimatic Variables in Upper Awash River Basin, Ethiopia

Daba

Ayele

Suning

2020

Advances in Meteorology

View full text Add to dashboard Cite

show abstract

“…To determine trends and test their significances, non‐parametric methods were used, as recommended by Kundzewicz and Robson (2004) and applied in other studies (e.g., Folton et al, 2019). The Theil–Sen method was used to estimate the change over time, and the Mann‐Kendall test was used to test the null hypothesis that there was no change.…”

Section: Methodsmentioning

confidence: 99%

Hydrological trends and the evolution of catchment research in the Alptal valley, central Switzerland

Stähli

Seibert

Kirchner

et al. 2021

Hydrological Processes

View full text Add to dashboard Cite

When the observation of small headwater catchments in the pre-Alpine Alptal valley (central Switzerland) started in the late 1960s, the researchers were mainly interested in questions related to floods and forest management. Investigations of geomorphological processes in the steep torrent channels followed in the 1980s, along with detailed observations of biogeochemical and ecohydrological processes in individual forest stands. More recently, research in the Alptal has addressed the impacts of climate change on water supply and runoff generation. In this article, we describe, for the first time, the evolution of catchment research at Alptal, and present new analyses of longterm trends and short-term hydrologic behaviour. Hydrometeorological time series from the past 50 years show substantial interannual variability, but only minimal long-term trends, except for the 2 C increase in mean annual air temperature over the 50-year period, and a corresponding shift towards earlier snowmelt. Similar to previous studies in larger Alpine catchments, the decadal variations in mean annual runoff in Alptal's small research catchments reflect the long-term variability in annual precipitation. In the Alptal valley, the most evident hydrological trends were observed in late spring and are related to the substantial change in the duration of the snow cover. Streamflow and water quality are highly variable within and between hydrological events, suggesting rapid shifts in flow pathways and mixing, as well as changing connectivity of runoffgenerating areas. This overview illustrates how catchment research in the Alptal has evolved in response to changing societal concerns and emerging scientific questions.

show abstract

“…For instance, the Vaubarnier catchment (Réal Collobrier Observatory, Figure 3a) is typical of the Mediterranean climate, which is known for its warm, dry summers and intense storm events, which occur mainly in autumn (Drobinski et al, 2014). In the context of climate change, an annual increase in temperature and reference evapotranspiration but no significant trends in annual precipitation were detected on the Réal Collobrier catchments, decreasing the amount of water available (Folton et al, 2019). However, flows responded not only to the magnitude of changes in precipitation and temperature, but also to the timing of these changes.…”

Section: Representation Of Diversity Of Occurrences Origins and Evolutions Of Ires Within Czo And Ltser And The Need For Integrated Appromentioning

confidence: 99%

“…Contrasting trends of intermittent stream flow in two OZCAR observatories. (a) In the Vaubarnier catchment (Réal Collobrier Observatory, France), there is a significant decreasing trend of monthly flows for March from 1967–2017 (Sen's slope of linear trend = −0.862 mm/month, adapted from Folton et al (2019), data are available on the BDOH database: https://bdoh.irstea.fr/REAL‐COLLOBRIER/). (b) In Agoufou catchment (Amma‐Catch Observatory, Mali), annual inflow into Lake Agoufou clearly increased from 1960–1990 to 2000–2015 (data sets: DOI: 10.17178/AMMA‐CATCH.CL.Rain_GT and 10.17178/AMMA‐CATCH.CL.Pond_Gha)…”

Section: Representation Of Diversity Of Occurrences Origins and Evolutions Of Ires Within Czo And Ltser And The Need For Integrated Appromentioning

confidence: 99%

Intermittent rivers and ephemeral streams: Perspectives for critical zone science and research on socio‐ecosystems

et al. 2021

Self Cite

View full text Add to dashboard Cite

Intermittent rivers and ephemeral streams (IRES) are now recognized to support specific freshwater biodiversity and ecosystem services and represent approximately half of the global river network, a fraction that is likely to increase in the context of global changes. Despite large research efforts on IRES during the past few decades, there is a need for developing a systemic approach to IRES that considers their hydrological, hydrogeological, hydraulic, ecological, and biogeochemical properties and processes, as well as their interactions with human societies. Thus, we assert that the interdisciplinary approach to ecosystem research promoted by critical zone sciences and socio‐ecology is relevant. These approaches rely on infrastructure—Critical Zone Observatories (CZO) and Long‐Term Socio‐Ecological Research (LTSER) platforms—that are representative of the diversity of IRES (e.g., among climates or types of geology. We illustrate this within the French CZO and LTSER, including their diversity as socio‐ecosystems, and detail human interactions with IRES. These networks are also specialized in the long‐term observations required to detect and measure ecosystem responses of IRES to climate and human forcings despite the delay and buffering effects within ecosystems. The CZO and LTSER platforms also support development of innovative techniques and data analysis methods that can improve characterization of IRES, in particular for monitoring flow regimes, groundwater‐surface water flow, or water biogeochemistry during rewetting. We provide scientific and methodological perspectives for which this interdisciplinary approach and its associated infrastructure would provide relevant and original insights that would help fill knowledge gaps about IRES. This article is categorized under: Water and Life > Stresses and Pressures on Ecosystems Science of Water > Hydrological Processes Water and Life > Conservation, Management, and Awareness

show abstract

A 50-year analysis of hydrological trends and processes in a Mediterranean catchment

Cited by 4 publications

References 28 publications

Long-Term Homogeneity and Trends of Hydroclimatic Variables in Upper Awash River Basin, Ethiopia

Long-Term Homogeneity and Trends of Hydroclimatic Variables in Upper Awash River Basin, Ethiopia

Hydrological trends and the evolution of catchment research in the Alptal valley, central Switzerland

Intermittent rivers and ephemeral streams: Perspectives for critical zone science and research on socio‐ecosystems

Contact Info

Product

Resources

About