Analysis of Salt Lake Volume Dynamics Using Sentinel-1 Based SBAS Measurements: A Case Study of Lake Tuz, Turkey

As one of the largest hypersaline lakes, Lake Tuz, located in the middle of Turkey, is a key waterbird habitat and is classified as a Special Environmental Protection Area in the country. It is a dynamic lake, highly affected by evaporation due to its wide expanse and shallowness (water depth <40 cm), in addition to being externally exploited by salt companies. Monitoring the dynamics of its changes in volume, which cause ecological problems, is required to protect its saline lake functions. In this context, a spatially homogeneous distributed gauge could be critical for monitoring and rapid response; however, the number of gauge stations and their vicinity is insufficient for the entire lake. The present study focuses on assessing the feasibility of a time-series interferometric technique, namely the small baseline subset (SBAS), for monitoring volume dynamics, based on freely available Sentinel-1 data. A levelling observation was also performed to quantify the accuracy of the SBAS results. Regression analysis between water levels, which is one of the most important volume dynamics, derived by SBAS and levelling in February, April, July and October was 67%, 80%, 84%, and 95% respectively, for correlation in the range of 10–40 cm in water level, and was in line with levelling. Salt lake components such as water, vegetation, moist soil, dry soil, and salt, were also classified with Sentinel-2 multispectral images over time to understand the reliability of the SBAS measurements based on interferometric coherence over different surface types. The findings indicate that the SBAS method with Sentinel-1 is a good alternative for measuring lake volume dynamics, including the monitoring of water level and salt movement, especially for the dry season. Even though the number of coherent, measurable, samples (excluding water) decrease during the wet season, there are always sufficient coherent samples (>0.45) over the lake.

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Large scale constructed wetland implementation projects in Turkey in Salt Lake Special Environmental Protection Area

Desalination and Water Treatment ◽

10.1080/19443994.2013.791779 ◽

2013 ◽

Vol 51 (22-24) ◽

pp. 4758-4767

Author(s):

Kemal Gunes ◽

Beyhan Oktar ◽

Selma Ayaz ◽

Asli Suha Gunay ◽

Gurkan Ozden ◽

...

Keyword(s):

Environmental Protection ◽

Constructed Wetland ◽

Large Scale ◽

Salt Lake ◽

Environmental Protection Area ◽

Protection Area

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Effects of a Surfactant Seed Coating on Alkali Bulrush Germination and Biomass

Journal of Student Research ◽

10.47611/jsr.vi.452 ◽

2018 ◽

Author(s):

Anders Hart ◽

Emily Martin ◽

Matthew Madsen ◽

Karin Kettenring

Keyword(s):

Water Level ◽

Migratory Birds ◽

Salt Lake ◽

Water Repellency ◽

Water Levels ◽

High Dose ◽

Seed Coating ◽

Seedling Height ◽

Water Demands ◽

Soil Moisture Availability

Great Salt Lake (GSL) wetlands provide vital ecosystem services, including habitat for migratory birds. Alkali bulrush (Bolboschoenus maritimus) plays an important role in providing these services, but invasion by Phragmites australis has reduced the extent of alkali bulrush stands in GSL wetlands. Restoring alkali bulrush is a primary goal for GSL managers following Phragmites removal. However, rising temperatures and changing precipitation patterns with climate change, as well increasing human water demands upstream, may alter the hydropattern of GSL wetlands, thus lowering soil moisture availability and potentially inhibiting alkali bulrush germination and seedling establishment. Surfactant seed coatings have been effective in aiding the germination of seeds in upland restoration sites by reducing soil water repellency, but have not been tested in wetlands. We tested whether the addition of a surfactant seed coating to alkali bulrush seeds improved germination at four water levels in a greenhouse. Water level and seed coating were significantly associated with improved germination. In a second experiment, we tested the effect of the seed coating at a low and high dose and staggered water level drawdowns on seedling height and biomass over six weeks. Seed coating and time of water level drop were not significantly associated with differences in seedling height. The water level decrease may not have been extreme enough to negatively affect seedlings. More research is needed to determine if a surfactant seed coating enhances alkali bulrush germination and growth under less favorable water availability conditions.

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River Discharge and Water Level Changes in the Mekong River: Droughts in an Era of Mega-Dams

10.22541/au.161189206.60684509/v1 ◽

2021 ◽

Author(s):

XiXi Lu ◽

Samuel Chua

Keyword(s):

Water Level ◽

Water Discharge ◽

Dry Season ◽

Water Levels ◽

Mekong River ◽

Wet Season ◽

Discharge Data ◽

Mekong Basin ◽

Lower Mekong Basin ◽

Dry Conditions

While 1992 marked the first major dam – Manwan – on the main stem of the Mekong River, the post-2010 era has seen the construction and operationalisation of mega dams such as Xiaowan (started operations in 2010) and Nuozhadu (started operations in 2014) that were much larger than any dams built before. The scale of these projects implies that their operations will likely have significant ecological and hydrological impacts from the Upper Mekong Basin to the Vietnamese Delta and beyond. Historical water level and water discharge data from 1960 to 2020 were analysed to examine the changes to streamflow conditions across three time periods: 1960-1991 (pre-dam), 1992-2009 (growth) and 2010-2020 (mega-dam). At Chiang Saen, the nearest station to the China border, monthly water discharge in the mega-dam period has increased by up to 98% during the dry season and decreased up as much as -35% during the wet season when compared to pre-dam records. Similarly, monthly water levels also rose by up to +1.16m during the dry season and dropped by up to -1.55m during the wet season. This pattern of hydrological alterations is observed further downstream to at least Stung Treng (Cambodia) in our study, showing that Mekong streamflow characteristics have shifted substantially in the post-2010 era. In light of such changes, the 2019-2020 drought – the most severe one in the recent history in the Lower Mekong Basin – was a consequent of constructed dams reducing the amount of water during the wet season. This reduction of water was exacerbated by the decreased monsoon precipitation in 2019. Concurrently, the untimely operationalisation of the newly opened Xayaburi dam in Laos coincided with the peak of the 2019-2020 drought and could have aggravated the dry conditions downstream. Thus, the mega-dam era (post-2010) may signal the start of a new normal of wet-season droughts.

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Water levels affect photosynthesis and nutrient use more than salinity in a scrub Red Mangrove forest of the southeastern Florida Everglades

10.1101/2021.01.27.428494 ◽

2021 ◽

Author(s):

J. Aaron Hogan ◽

Edward Castañeda-Moya ◽

Lukas Lamb-Wotton ◽

Christopher Baraloto

Keyword(s):

Water Level ◽

Mangrove Forest ◽

Leaf Gas Exchange ◽

Critical Role ◽

Dry Season ◽

Water Levels ◽

Marginal Effect ◽

Mangrove Forests ◽

Wet Season ◽

Porewater Salinity

AbstractPhotosynthesis is an essential process to mangrove forest carbon cycling, which plays a critical role in the global carbon cycle. We investigated how differences in mangrove island micro-elevation (i.e., habitat) affect tree physiology in a scrub mangrove forests of the southeastern Everglades. We measured leaf gas exchange rates of scrub Rhizophora mangle trees monthly during 2019, hypothesizing that CO2 assimilation (Anet) and stomatal conductance (gsw) would decline with increases in water level and salinity, with larger differences at mangrove islands edges than centers, where inundation and salt stress are greatest. Water levels varied between 0 and 60 cm, rising during the wet season (May-October) relative to the dry season (November-April). Porewater salinity ranged from 15 to 30 ppt, being higher at mangrove island edges compared to centers. Anet maximized at 15.1 µmol m-2 s-1, and gsw was typically <0.2 mol m-2 s-1, both of which were greater in the dry than the wet season and greater at mangrove island centers than edges. After accounting for season and habitat, water level had a positive effect on Anet in both seasons, but no effect on gsw. Similarly, porewater salinity had a slightly positive marginal effect on Anet but a negligible effect on gsw Our findings suggest that water levels drive variation in Anet more than salinity in Everglades scrub mangroves, while also constraining Anet more than gsw, and that the interaction between permanent flooding and habitat varies with season as physiological stress is alleviated at higher-elevation mangrove island center habitats in the dry season. Additionally, habitat heterogeneity leads to differences in nutrient and water acquisition and use between trees growing in island centers versus edges, creating distinct physiological controls on leaf physiology and photosynthesis which could ultimately affect carbon flux dynamics of scrub mangrove forests across the Everglades landscape.

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AGRICULTURAL WATER-GATE MANAGEMENT FOR OPERATIONAL FLOOD PROTECTION IN LOW-LYING PADDIES

Jurnal Teknologi ◽

10.11113/jt.v76.5950 ◽

2015 ◽

Vol 76 (15) ◽

Author(s):

Yumi Yoshioka ◽

Takao Masumoto ◽

Kazuhiko Maruyama ◽

Hiroki Minakawa

Keyword(s):

Water Level ◽

Circulation Model ◽

Water Levels ◽

Flood Protection ◽

Main Stream ◽

Agricultural Water ◽

Wet Season ◽

Gate Operation ◽

Water Gate ◽

Outer Water

It is essential to assess in influence of water-gate operations on inundation processes during the wet season to mitigate inundation damage. Here, a numerical analysis method for modelling regional drainage through water gates was developed by integrating the Distributed Water Circulation Model incorporating Agricultural Water Use (DWCM-AgWU). The inundation process was reproduced using an H–V curve (flooding water level verses area volume). The developed model was applied to the low-lying paddy areas of the Nam Cheng River basin in the Lao PDR. This study area is a sub-basin of the Nam Ngum River, with which the Nam Cheng River merges downstream of the Nam Ngum 1 dam. Fourteen agricultural water gates of slide-type at the river outlet function as a storage facility for irrigation water for the paddies during the dry season and as a flood protection measures against backwater effects from the main stream of the Nam Ngum River during the wet season. However, current gate operation is based on empirical knowledge without reference to filed observational data. The simulated results revealed that the outer water level did not exceed the inner level, if the difference between the inner and outer water levels was > 4 m on operational days. Several feedback control strategies combined with gate opening heights, the number of open gates, operation intervals, and the threshold inner and outer water level differences were examined focusing on inundation damage within the area and drainage volume through the gates.

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Three-Parameter Regulation Rules for the Long-Term Optimal Scheduling of Multiyear Regulating Storage Reservoirs

Water ◽

10.3390/w13243593 ◽

2021 ◽

Vol 13 (24) ◽

pp. 3593

Author(s):

Yangyang Xie ◽

Saiyan Liu ◽

Hongyuan Fang ◽

Maohua Ding ◽

Jingcai Wang

Keyword(s):

Water Level ◽

Yellow River ◽

Cuckoo Search ◽

Water Levels ◽

Optimal Scheduling ◽

Wet Season ◽

Decision Variables ◽

Inflow Condition ◽

Multireservoir System

The perennial storage water level (PL), the water level at the end of wet season (WL), and the water level at the end of dry season (DL) are three critical water levels for multiyear regulating storage (MRS) reservoirs. Nevertheless, the three critical water levels have not been paid enough attention, and there is no general method that calculates them in light of developing regulating rules for MRS reservoirs. In order to address the issue, three-parameter regulation (TPR) rules based on the coordination between the intra- and interannual regulation effects of MRS reservoirs are presented. Specifically, a long-term optimal scheduling (LTOS) model is built for maximizing the multiyear average hydropower output (MAHO) of a multireservoir system. The TPR rules are a linear form of rule with three regulation parameters (annual, storage, and release regulation parameters), and use the cuckoo search (CS) algorithm to solve the LTOS model with three regulation parameters as the decision variables. The approach of utilizing the CS algorithm to solve the LTOS model with the WL and DL as the decision variables is abbreviated as the OPT approach. Moreover, the multiple linear regression (MLR) rules and the artificial neural network (ANN) rules are derived from the OPT approach-based water-level processes. The multireservoir system at the upstream of Yellow River (UYR) with two MRS reservoirs, Longyangxia (Long) and Liujiaxia (Liu) reservoirs, is taken as a case study, where the TPR rules are compared with the OPT approach, the MLR rules, and the ANN rules. The results show that for the UYR multireservoir system, (1) the TPR rules-based MAHO is about 0.3% (0.93 × 108 kW∙h) more than the OPT approach-based MAHO under the historical inflow condition, and the elapsed time of the TPR rules is only half of that of the OPT approach; (2) the TPR rules-based MAHO is about 0.79 × 108 kW∙h more than the MLR/ANN rules-based MAHO under the historical inflow condition, and the TPR rules can realize 0.1–0.4% MAHO more than the MLR and ANN rules when the reservoir inflow increases or reduces by 10%. According to the annual regulation parameter, the PLs of Long and Liu reservoirs are 2572.3 m and 1695.2 m, respectively. Therefore, the TPR rules are an easy-to-obtain and adaptable LTOS rule, which could reasonably and efficiently to determine the three critical water levels for MRS reservoirs.

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AUTOMATIC WATER LEVEL MONITORING WITH IOT AND LPWAN

International Conference on Technics Technologies and Education ◽

10.15547/ictte.2019.02.041 ◽

2019 ◽

pp. 95-103

Author(s):

Krum Videnov ◽

Vanya Stoykova

Keyword(s):

Water Level ◽

Real Time ◽

Early Warning ◽

Water Sources ◽

Water Levels ◽

Water Level Fluctuations ◽

Level Monitoring ◽

Water Level Monitoring

Monitoring water levels of lakes, streams, rivers and other water basins is of essential importance and is a popular measurement for a number of different industries and organisations. Remote water level monitoring helps to provide an early warning feature by sending advance alerts when the water level is increased (reaches a certain threshold). The purpose of this report is to present an affordable solution for measuring water levels in water sources using IoT and LPWAN. The assembled system enables recording of water level fluctuations in real time and storing the collected data on a remote database through LoRaWAN for further processing and analysis.

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