spring discharge
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2022 ◽  
Author(s):  
Fatemeh Geravand ◽  
Seiyed Mossa Hosseini ◽  
Mehran Maghsoudi ◽  
Mojtaba Yamani

Abstract Karst groundwater resources in the Zagros Mountains are vital for supplying of different demands in the region which need to sustainable management and protection. Quantitative and qualitative characterization of karst aquifers in this region were understudied due to lack of site-specific logging-data and speleological investigations. In this study, a state-of-the-art of the statistical methods developed to characterize karst aquifer based on analyses of the spring recession hydrograph and spring water quality are presented. These methods including Manging’s method for classification of karst aquifers, relationships of precipitation and discharge data, groundwater quality index (GQI), hydrochemical diagrams (Piper, Durov and Gibbs), and Saturation index (SI), Chloro-Alkaline indices (CAI). 42 major karst springs mainly located in folded part of Zagros region (western Iran) are selected for application of the reviewed methods. Results indicated that the saturated zone exerts almost main control over the discharge of 76% of the studied springs. The base-flow contributes as between 80.0% to 100% of total water storage in the study aquifers. 78.5% of the studied aquifers have a high karstification degree. An insignificant lag-time is observed between the precipitation on the karst basin and spring discharge. The hydrochemical diagrams show that the waters are dominated by HCO3 and Ca and the majority of the waters are alkaline, with originate from silicate minerals weathering. Such repeatable methods adopted in this study can provide crucial information of the karst aquifers, especially those suffer scarcity of aquifer hydrodynamic data.


2021 ◽  
Vol 6 (2) ◽  
pp. 140
Author(s):  
Adiyanto Adiyanto ◽  
Muhammad Ramli ◽  
Hasbullah Syaf

The provision of clean water to meet the needs of the community is something important, and the availability of clean water must be considered in order to meet the needs of the community, especially in Kendari City. This study aims to analyze the availability of raw water at the Regional Water Company (PDAM) Tirta Anoa Kendari City. The method used is the method of raw water availability by using discharge data from the Pohara River and the Wanggu River in 2010-2019. The results of this study are the availability of raw clean water at PDAM Kendari City is the production discharge of 300 ltr/second, the production discharge of Matabondu Springs of 50 l/second, the production discharge of the Wanggu River of 20 l/second, and the Anduonohu spring discharge of 5 ltr. /sec and Anggoeya at 40 liters/sec Keywords: raw water, availability, PDAMPenyedian air bersih untuk memenuhi kebutuhan masyarakat merupakan sesuatu yang penting, dan ketersediaan air bersih harus diperhatikan agar dapat memenuhi kebutuhan masyarakat, khususnya di Kota Kendari. Penelitian ini bertujuan untuk menganalisis ketersediaan air baku pada Perusahaan Daerah Air Minum (PDAM) Tirta Anoa Kota Kendari. Metode yang digunakan yaitu metode ketersediaan air baku dengan menggunakan data debit Sungai Pohara dan Sungai Wanggu tahun 2010-2019. Hasil Penelitian ini yaitu ketersediaan air bersih baku pada PDAM Kota Kendari adalah debit produksi sebesar 300 ltr/detik, debit produksi Mata Air Matabondu sebesar 50 l/detik, debit produksi Sungai Wanggu sebesar 20 l/detik, dan debit Mata air Anduonohu sebesar 5 ltr/dtk dan Anggoeya sebesar 40 liter/dtk Kata Kunci : Air Baku, Ketersediaan, PDAM


2021 ◽  
Author(s):  
◽  
Steven James Harding

<p>This thesis is a study of the sub-harbour Waiwhetu Artesian Aquifer, and in particular the nature and characteristics of artesian leakage from submarine springs. This aquifer is a sheet of gravel and other coarse sediments which continues from the Lower Hutt Valley and extends beneath Wellington Harbour where it varies in thickness from approximately 70m against the Wellington Fault scarp to just over 20m thick against the eastern harbour margin. The water it contains is a valuable resource supplying approximately one third of Wellington's municipal water consumption.  At present, there are plans to utilise this artesian water source to a greater extent in the future, to support a greater burden of the region's water requirements. However concerns over possible salt-water intrusion and contamination of the aquifer led to an interest in developing a better understanding of the characteristics of this artesian system, particularly beneath the harbour floor.  Harbour floor depressions were selected as likely sources of artesian water leakage based on the presumption that they had been formed by the action of leaking artesian water from beneath. Eleven depression 'zones' were investigated by recording the salinity of the water within the depressions using a portable conductivity/temperature meter. SCUBA diver's observations and bathymetric mapping revealed that depressions ranged in width from 53m to 369m (at the harbour floor) and 12m to 69m (at the depression base), with depths ranging from 13.3m to 31.3m below sea level.  Only a few depressions were found to be actively discharging significant amounts of artesian water. SCUBA diver investigations found this leakage to be typically concentrated at a number of small and discrete spring 'vents' located on the base of the active depression. Typical salinities recorded ranged from 28 - 33 ppt within a few centimetres of the discharge vents. Deployment of an S4 current meter in two depressions showed that spring vent discharges vary with the pattern of abstraction from the pumping stations in the Lower Hutt Valley and as a consequence of the tidal cycle. High tides generate a greater load on the underlying aquifer, which in turn compresses the aquifer structure to a greater extent than at low tides, thus 'squeezing' out more water.  Almost all of the recorded leakage was found to occur from a cluster of submarine springs within one of the depression zones, roughly 1100 metres from the Hutt River mouth. One other notable area of leakage was found close to Seaview Wharf. No significant leakage was observed or recorded from the two deep depressions south of Somes Island, which had previously been considered to be the major outlet of artesian leakage in the harbour.  Lower than normal salinity values were also recorded in the harbour entrance. In this region the aquiclude is hypothesised to peter out, allowing artesian water to escape from the aquifer through a large area of the seabed in the form of widespread leakage as opposed to the concentrated, or discrete, form associated with spring vent discharge.  Seismic profiles were used to map the extent of the sub-harbour Waiwhetu Artesian Aquifer and its upper confining aquiclude, the Petone Marine Beds. This work showed that the aquifer gravels extend across the entire harbour area. However, the water-bearing capacity of these deposits was found to be inconsistent. Preferential pathways, present as paleochannels (relic river channels), can be mapped within the aquifer. They concentrate the flow of groundwater through the aquifer and as such supply the submarine spring regions with much higher rates of water flow than the inter-paleochannel areas.  The harbour floor depressions are thought to have formed as a consequence of the deformation of aquifer and aquiclude deposits during intense shaking associated with earthquakes leading to the removal of portions of the confining aquiclude. This typically occurs from a combination of raised piezometric pressures as a result of consolidation of the aquifer material during shaking, and from failure of the aquiclude by liquefaction. This rupture of the aquiclude results in the release of large volumes of artesian water through the aquiclude and to the sea. As this flow of water moves upward through the aquiclude, it erodes and transports away the fine sediment that forms this member. The features left behind are the characteristic harbour floor depressions we associate with submarine spring discharge.  The abstraction of water from the Waiwhetu Artesian Aquifer (for the Wellington municipal water supply) lowers the piezometric pressure within the aquifer close to the abstraction zone. As such, the relocation of the abstraction focus (during 1980) to three kilometres inland from Petone Foreshore has greatly improved the 'health' of the subharbour aquifer and has similarly reduced the threat of salt-water intrusion.  Data gathered during this study implies that while the two deep depressions south of Somes Island are unlikely to be a threat with regard to salt-water intrusion, the cluster of depressions off the Hutt River mouth could be a site of salt-water entry if piezometric pressures in the aquifer beneath them dropped low enough. Spring discharge velocities collected over one spring vent indicate that the presently set minimum piezometric Petone Foreshore level (below which abstraction must cease) needs to be revised.</p>


2021 ◽  
Author(s):  
◽  
Steven James Harding

<p>This thesis is a study of the sub-harbour Waiwhetu Artesian Aquifer, and in particular the nature and characteristics of artesian leakage from submarine springs. This aquifer is a sheet of gravel and other coarse sediments which continues from the Lower Hutt Valley and extends beneath Wellington Harbour where it varies in thickness from approximately 70m against the Wellington Fault scarp to just over 20m thick against the eastern harbour margin. The water it contains is a valuable resource supplying approximately one third of Wellington's municipal water consumption.  At present, there are plans to utilise this artesian water source to a greater extent in the future, to support a greater burden of the region's water requirements. However concerns over possible salt-water intrusion and contamination of the aquifer led to an interest in developing a better understanding of the characteristics of this artesian system, particularly beneath the harbour floor.  Harbour floor depressions were selected as likely sources of artesian water leakage based on the presumption that they had been formed by the action of leaking artesian water from beneath. Eleven depression 'zones' were investigated by recording the salinity of the water within the depressions using a portable conductivity/temperature meter. SCUBA diver's observations and bathymetric mapping revealed that depressions ranged in width from 53m to 369m (at the harbour floor) and 12m to 69m (at the depression base), with depths ranging from 13.3m to 31.3m below sea level.  Only a few depressions were found to be actively discharging significant amounts of artesian water. SCUBA diver investigations found this leakage to be typically concentrated at a number of small and discrete spring 'vents' located on the base of the active depression. Typical salinities recorded ranged from 28 - 33 ppt within a few centimetres of the discharge vents. Deployment of an S4 current meter in two depressions showed that spring vent discharges vary with the pattern of abstraction from the pumping stations in the Lower Hutt Valley and as a consequence of the tidal cycle. High tides generate a greater load on the underlying aquifer, which in turn compresses the aquifer structure to a greater extent than at low tides, thus 'squeezing' out more water.  Almost all of the recorded leakage was found to occur from a cluster of submarine springs within one of the depression zones, roughly 1100 metres from the Hutt River mouth. One other notable area of leakage was found close to Seaview Wharf. No significant leakage was observed or recorded from the two deep depressions south of Somes Island, which had previously been considered to be the major outlet of artesian leakage in the harbour.  Lower than normal salinity values were also recorded in the harbour entrance. In this region the aquiclude is hypothesised to peter out, allowing artesian water to escape from the aquifer through a large area of the seabed in the form of widespread leakage as opposed to the concentrated, or discrete, form associated with spring vent discharge.  Seismic profiles were used to map the extent of the sub-harbour Waiwhetu Artesian Aquifer and its upper confining aquiclude, the Petone Marine Beds. This work showed that the aquifer gravels extend across the entire harbour area. However, the water-bearing capacity of these deposits was found to be inconsistent. Preferential pathways, present as paleochannels (relic river channels), can be mapped within the aquifer. They concentrate the flow of groundwater through the aquifer and as such supply the submarine spring regions with much higher rates of water flow than the inter-paleochannel areas.  The harbour floor depressions are thought to have formed as a consequence of the deformation of aquifer and aquiclude deposits during intense shaking associated with earthquakes leading to the removal of portions of the confining aquiclude. This typically occurs from a combination of raised piezometric pressures as a result of consolidation of the aquifer material during shaking, and from failure of the aquiclude by liquefaction. This rupture of the aquiclude results in the release of large volumes of artesian water through the aquiclude and to the sea. As this flow of water moves upward through the aquiclude, it erodes and transports away the fine sediment that forms this member. The features left behind are the characteristic harbour floor depressions we associate with submarine spring discharge.  The abstraction of water from the Waiwhetu Artesian Aquifer (for the Wellington municipal water supply) lowers the piezometric pressure within the aquifer close to the abstraction zone. As such, the relocation of the abstraction focus (during 1980) to three kilometres inland from Petone Foreshore has greatly improved the 'health' of the subharbour aquifer and has similarly reduced the threat of salt-water intrusion.  Data gathered during this study implies that while the two deep depressions south of Somes Island are unlikely to be a threat with regard to salt-water intrusion, the cluster of depressions off the Hutt River mouth could be a site of salt-water entry if piezometric pressures in the aquifer beneath them dropped low enough. Spring discharge velocities collected over one spring vent indicate that the presently set minimum piezometric Petone Foreshore level (below which abstraction must cease) needs to be revised.</p>


2021 ◽  
Vol 12 ◽  
Author(s):  
Alexandre F. Nolin ◽  
Jacques C. Tardif ◽  
France Conciatori ◽  
Yves Bergeron

In northeastern boreal Canada, the long-term perspective on spring flooding is hampered by the absence of long gage records. Changes in the tree-ring anatomy of periodically flooded trees have allowed the reconstruction of historical floods in unregulated hydrological systems. In regulated rivers, the study of flood rings could recover past flood history, assuming that the effects of hydrological regulation on their production can be understood. This study analyzes the effect of regulation on the flood-ring occurrence (visual intensity and relative frequency) and on ring widths in Fraxinus nigra trees growing at five sites distributed along the Driftwood River floodplain. Driftwood River was regulated by a dam in 1917 that was replaced at the same location in 1953. Ring width revealed little, to no evidence, of the impact of river regulation, in contrast to the flood rings. Prior to 1917, high relative frequencies of well-defined flood rings were recorded during known flood years, as indicated by significant correlations with reconstructed spring discharge of the nearby Harricana River. After the construction and the replacement of the dam, relative frequencies of flood rings and their intensities gradually decreased. Flood-ring relative frequencies after 1917, and particularly after 1953, were mostly composed of weakly defined (less distinct) flood rings with some corresponding to known flood years and others likely reflecting dam management. The strength of the correlations with the instrumental Harricana River discharge also gradually decrease starting after 1917. Compared with upper floodplain trees, shoreline trees at each site recorded flood rings less frequently following the construction of the first but especially of the second dam, indicating that water level regulation limited flooding in the floodplains. Compared with the downstream site to the dam, the upstream ones recorded significantly more flood rings in the postdam period, reemphasizing the importance of considering the position of the site along with the river continuum and site conditions in relation to flood exposure. The results demonstrated that sampling trees in multiple riparian stands and along with various hydrological contexts at a far distance of the dams could help disentangle the flooding signal from the dam management signal.


2021 ◽  
Author(s):  
Ignacio Hermoso de Mendoza ◽  
Etienne Boucher ◽  
Fabio Gennaretti ◽  
Aliénor Lavergne ◽  
Laia Andreu-Hayles ◽  
...  

Abstract. The representation of snow processes in forest growth models is necessary to accurately predict the hydrological cycle in boreal ecosystems and the isotopic signature of soil water extracted by trees, photosynthates and tree-ring cellulose. Yet, most process-based models do not include a snow module, consequently their simulations may be biased in cold environments. Here, we modified the MAIDENiso model to incorporate a new snow module that simulates snow accumulation, melting and sublimation, as well as thermal exchanges driving freezing and thawing of the snow and the soil. We tested these implementations in two sites in East and West Canada for black spruce (Picea mariana) and white spruce (Picea glauca) forests, respectively. The new snow module improves the skills of the model to predict components of the hydrological cycle. The model is now able to reproduce the spring discharge peak and to simulate stable oxygen isotopes in tree-ring cellulose more realistically than in the original, snow-free version of the model. The new implementation also results in simulations with a higher contribution from the source water on the oxygen isotopic composition of the simulated cellulose, leading to more accurate estimates. Future work may include the development of inverse modelling with the new version of MAIDENiso to produce robust reconstructions of the hydrological cycle and isotope processes in cold environments.


PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0256586
Author(s):  
Michael T. Tercek ◽  
David Thoma ◽  
John E. Gross ◽  
Kirk Sherrill ◽  
Stefanie Kagone ◽  
...  

A robust method for characterizing the biophysical environment of terrestrial vegetation uses the relationship between Actual Evapotranspiration (AET) and Climatic Water Deficit (CWD). These variables are usually estimated from a water balance model rather than measured directly and are often more representative of ecologically-significant changes than temperature or precipitation. We evaluate trends and spatial patterns in AET and CWD in the Continental United States (CONUS) during 1980–2019 using a gridded water balance model. The western US had linear regression slopes indicating increasing CWD and decreasing AET (drying), while the eastern US had generally opposite trends. When limits to plant performance characterized by AET and CWD are exceeded, vegetation assemblages change. Widespread increases in aridity throughout the west portends shifts in the distribution of plants limited by available moisture. A detailed look at Sequoia National Park illustrates the high degree of fine-scale spatial variability that exists across elevation and topographical gradients. Where such topographical and climatic diversity exists, appropriate use of our gridded data will require sub-setting to an appropriate area and analyzing according to categories of interest such as vegetation communities or across obvious physical gradients. Recent studies have successfully applied similar water balance models to fire risk and forest structure in both western and eastern U.S. forests, arid-land spring discharge, amphibian colonization and persistence in wetlands, whitebark pine mortality and establishment, and the distribution of arid-land grass species and landscape scale vegetation condition. Our gridded dataset is available free for public use. Our findings illustrate how a simple water balance model can identify important trends and patterns at site to regional scales. However, at finer scales, environmental heterogeneity is driving a range of responses that may not be simply characterized by a single trend.


2021 ◽  
Author(s):  
Andreas Wunsch ◽  
Tanja Liesch ◽  
Guillaume Cinkus ◽  
Nataša Ravbar ◽  
Zhao Chen ◽  
...  

Abstract. Despite many existing approaches, modeling karst water resources remains challenging and often requires solid system knowledge. Artificial Neural Network approaches offer a convenient solution by establishing a simple input-output relationship on their own. However, in this context, temporal and especially spatial data availability is often an important constraint, as usually no or few climate stations within a karst spring catchment are available. Hence spatial coverage is often unsatisfying and can introduce severe uncertainties. To avoid these problems, we use 2D-Convolutional Neural Networks (CNN) to directly process gridded meteorological data followed by a 1D-CNN to perform karst spring discharge simulation. We investigate three karst spring catchments in the Alpine and Mediterranean region with different meteorologic-hydrological characteristics and hydrodynamic system properties. We compare our 2D-models both to existing modeling studies in these regions and to 1D-models, which use climate station data, as it is common practice. Our results show that our models are excellently suited to model karst spring discharge and rival the simulation results of existing approaches in the respective areas. The 2D-models learn relevant parts of the input data and by performing a spatial input sensitivity analysis we can further show their potential for karst catchment localization and delineation.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sophie Charvet ◽  
Eunsoo Kim ◽  
Ajit Subramaniam ◽  
Joseph Montoya ◽  
Solange Duhamel

AbstractSmall pigmented eukaryotes (⩽ 5 µm) are an important, but overlooked component of global marine phytoplankton. The Amazon River plume delivers nutrients into the oligotrophic western tropical North Atlantic, shades the deeper waters, and drives the structure of microphytoplankton (> 20 µm) communities. For small pigmented eukaryotes, however, diversity and distribution in the region remain unknown, despite their significant contribution to open ocean primary production and other biogeochemical processes. To investigate how habitats created by the Amazon river plume shape small pigmented eukaryote communities, we used high-throughput sequencing of the 18S ribosomal RNA genes from up to five distinct small pigmented eukaryote cell populations, identified and sorted by flow cytometry. Small pigmented eukaryotes dominated small phytoplankton biomass across all habitat types, but the population abundances varied among stations resulting in a random distribution. Small pigmented eukaryote communities were consistently dominated by Chloropicophyceae (0.8–2 µm) and Bacillariophyceae (0.8–3.5 µm), accompanied by MOCH-5 at the surface or by Dinophyceae at the chlorophyll maximum. Taxonomic composition only displayed differences in the old plume core and at one of the plume margin stations. Such results reflect the dynamic interactions of the plume and offshore oceanic waters and suggest that the resident small pigmented eukaryote diversity was not strongly affected by habitat types at this time of the year.


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