Use of 222Rn and δ18O-δ2H Isotopes in Detecting the Origin of Water and in Quantifying Groundwater Inflow Rates in an Alarmingly Growing Lake, Ethiopia

Seifu Kebede; Samson Zewdu

doi:10.3390/w11122591

Use of 222Rn and δ18O-δ2H Isotopes in Detecting the Origin of Water and in Quantifying Groundwater Inflow Rates in an Alarmingly Growing Lake, Ethiopia

Water ◽

10.3390/w11122591 ◽

2019 ◽

Vol 11 (12) ◽

pp. 2591

Author(s):

Seifu Kebede ◽

Samson Zewdu

Keyword(s):

Lake Area ◽

Flow Paths ◽

Groundwater Inflow ◽

Water Users ◽

Excess Water ◽

Ecological Changes ◽

Practical Engineering ◽

Stable Isotopes Of Water ◽

Lake Systems ◽

Large Farms

Dual Radon (222Rn) and δ18O-δ2H isotopes were utilized to (a) detect the origin of water, (b) pinpoint groundwater inflow zones and (c) determine rates of groundwater inflows in an expanding lake in central Ethiopia. The lake area expanded from 2 km2 to 50 km2 over the last 60 years, causing serious engineering and socio-economic challenge (inundation of urban utilities, irrigation farms, railways and roads; ecological changes in the lake; and threatening water salinization for water users downstream). Commensurate with the changes in volume, there was a change in salinity of the lake from a hypersaline (TDS 50 g/L) to a near freshwater (3 g/L) condition. 222Rn is powerful in pinpointing sites of groundwater inflows and determining groundwater inflow rates in lake systems with non-hydrologic steady-state conditions. The 222Rn method is complemented by the use of the stable isotopes of water (δ18O-δ2H pair). The δ18O-δ2H isotopes were used to discriminate the source of the water responsible for the expansion of the lake. The results show that the main source of water responsible for the expansion of the lake is the irrigation of excess water joining the lake through subsurface flow paths. The fast and voluminous flow is aided by a dense network of faults and by seismically induced modern ground-cracks that enhance the transmissivity of the aquifers to as high as 15,000 m2/day. The 222Rn mass balance shows the groundwater inflow rate is estimated at 4.6 m3/s. This is comparable with the 4.9 m3/s annual seepage loss from three large farms in the area. This work adds to the meager literature in the use of 222Rn in lake-groundwater interaction studies by demonstrating the capability of the method in addressing a practical engineering and socio-economic challenges.

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Laying the Groundwork for Raising Awareness on Water Related Issues with a Socio-Hydrogeological Approach: The Inle Lake Case Study (Southern Shan State, Myanmar)

Water ◽

10.3390/w13172434 ◽

2021 ◽

Vol 13 (17) ◽

pp. 2434

Author(s):

Viviana Re ◽

Myat Mon Thin ◽

Chiara Tringali ◽

Mya Mya ◽

Enrico Destefanis ◽

...

Keyword(s):

Positive Impact ◽

Local Communities ◽

Added Value ◽

Monitoring Site ◽

Lake Area ◽

Structured Interviews ◽

Household Level ◽

Water Users ◽

Accessible Information ◽

The Impact

Translating scientific findings into concrete action for (ground)water protection should be fundamental component of any hydrogeological and hydrogeochemical assessment, thus ensuring that scientific outcomes have a positive impact in the real world. To this purpose, understanding the water-related issues and the perceived criticalities by the water users is an asset, especially for earth scientists who are often the first contact with local communities during in situ measurements. By presenting the results of a socio-hydrogeological assessment in the Inle Lake area, this paper aims at demonstrating the feasibility and added value of this approach. In conjunction with groundwater sampling, public engagement activities were conducted by administering semi-structured interviews at a household level in each monitoring site. Hydrogeochemical data show that groundwater is characterized by an elevated hardness and by the presence of trace metals in solution due to the low redox potential. The work provides suggestions on how to translate the hydrogeochemical information associated to (i) the impact of climate change on water supply and availability, and (ii) the presence of geogenic groundwater contamination (Fe, Mn, As) into accessible information for local communities and water users’ associations. Sharing knowledge and promoting capacity building would also help to assess the reasons for the discrepancy between self-reported perception of groundwater quality (e.g., hardness) and analytical results.

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Study of aquatic plants and ecological- physics Tempe Lake, Sulawesi Selatan

TORANI: Journal of Fisheries and Marine Science ◽

10.35911/torani.v2i2.7060 ◽

2019 ◽

Vol 2 (2) ◽

Author(s):

Media Fitri Isma Nugraha ◽

Atriyon Julzarika ◽

Alias Radjamuddin ◽

Reflinur Reflinur ◽

Rossa Yunita ◽

...

Keyword(s):

Aquatic Plants ◽

Lake Water ◽

Aquatic Plant ◽

Maximum Depth ◽

Lake Area ◽

Physical Conditions ◽

Inundation Area ◽

South Sulawesi ◽

Chemical Indicators ◽

Ecological Changes

Aquatic plants are an indicator of the fertility of an aquatic region. The waters of Lake Tempe are the largest waters of the lake area in South Sulawesi. Lake Tempe is located in the western part of Wajo District, precisely in Tempe District, about 7 km from Sengkang City towards the banks of the Walanae River in southern Sulawesi. The area is about 13,000 ha with a maximum depth of 5.5 m and can reach more than 30,000 ha during floods, and during the dry season, the inundation area reaches only 1,000 ha with a maximum depth of 1 m, located above the continental and Australian and Asian plates. This lake is one of the tectonic lakes in Indonesia. Every year silting the lake occurs. The Tempe hydro vegetation and eco-physical research were carried out in October 2017. The purpose of this study was to record aquatic plant species that live in Tempe Lake and observe ecological changes and physical properties of Lake Tempe. Aquatic plants are expected to be able to filter lake water. The results obtained are physical conditions of sharp-smelling water, unpleasant taste, dark brown, and cloudy color. Chemical indicators of NH3-N waters (0.2976-0.0634), PO4-P (0.0172-0.0844) NO2-N (undetectable), NO3-N (1.7131-1.9335), Sulphate (27.761900 - 37.047620), DO (6.88-7.18) and pH (7.88-8.02). There are 14 species of aquatic plants found in these waters. The most dominant species is water hyacinth. In the case of Tempe lake water vegetation results in siltation of the lake area.Keywords: Aquatic plant, Biodiversity, Species, Tempe lake,

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Research on Water Option Pricing Problem Based on the Binary Tree Model

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.955-959.3134 ◽

2014 ◽

Vol 955-959 ◽

pp. 3134-3137

Author(s):

Jin Mei Zhou ◽

Feng Ping Wu

Keyword(s):

Water Resources ◽

Binary Tree ◽

Water Rights ◽

Water Saving ◽

Market Mechanism ◽

Tree Model ◽

Put Options ◽

Water Users ◽

Excess Water ◽

American Put

Along with the progress of the water-saving technology, the water users who have excess water resources by using water saving technology may transfer the spare water rights to whom with water shortage. As a new attempt to water rights transaction, water options transaction has fully showed its efficiency and flexibility, and the water options pricing problem is the key problem in the process of trading. Using market mechanism enables water users participate in water rights transaction independently, water users who have excess water resources hold American put options based on the water rights, can use the binary tree pricing model to analyze the value of the American put option at various stages to help them deciding whether to perform rights or give up rights.

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Climatic Effects on Lake Basins. Part I: Modeling Tropical Lake Levels

Journal of Climate ◽

10.1175/2010jcli3602.1 ◽

2011 ◽

Vol 24 (12) ◽

pp. 2983-2999 ◽

Cited By ~ 9

Author(s):

Martina Ricko ◽

James A. Carton ◽

Charon Birkett

Keyword(s):

Lake Level ◽

Tropical Lakes ◽

Freshwater Flux ◽

Lake Area ◽

Lake Levels ◽

Seasonal Forecasts ◽

Climatic Effects ◽

Lakes And Reservoirs ◽

Lake Systems ◽

Observation Period

Abstract The availability of satellite estimates of rainfall and lake levels offers exciting new opportunities to estimate the hydrologic properties of lake systems. Combined with simple basin models, connections to climatic variations can then be explored with a focus on a future ability to predict changes in storage volume for water resources or natural hazards concerns. This study examines the capability of a simple basin model to estimate variations in water level for 12 tropical lakes and reservoirs during a 16-yr remotely sensed observation period (1992–2007). The model is constructed with two empirical parameters: effective catchment to lake area ratio and time delay between freshwater flux and lake level response. Rainfall datasets, one reanalysis and two satellite-based observational products, and two radar-altimetry-derived lake level datasets are explored and cross checked. Good agreement is observed between the two lake level datasets with the lowest correlations occurring for the two small lakes Kainji and Tana (0.87 and 0.89). Fitting observations to the simple basin model provides a set of delay times between rainfall and level rise ranging up to 105 days and effective catchment to lake ratios ranging between 2 and 27. For 9 of 12 lakes and reservoirs the observational rainfall products provide a better fit to observed lake levels than the reanalysis rainfall product. But for most of the records any of the rainfall products provide reasonable lake level estimates, a result which opens up the possibility of using rainfall to create seasonal forecasts of future lake levels and hindcasts of past lake levels. The limitations of the observation sets and the two-parameter model are discussed.

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Assessment of flow paths and groundwater storage processes in an island fractured rock aquifer system using the stable isotopes of water (H2O) and strontium (Sr), and environmental tracers’ tritium (3H) and sulfur hexafluoride (SF6).

10.5194/egusphere-egu21-12262 ◽

2021 ◽

Author(s):

Marsha Allen ◽

David Boutt

Keyword(s):

Stable Isotopes ◽

Sulfur Hexafluoride ◽

Fractured Rock ◽

Northern Region ◽

Effective Porosity ◽

Environmental Tracers ◽

Groundwater Storage ◽

Flow Paths ◽

The World ◽

Stable Isotopes Of Water

&#160;Access to fresh water is a critical humanitarian issue in many regions of the world and on the most important sustainable development goals. This crisis is exacerbated by the effects of climate change, pollutants, increases in demand and overuse. Fractured rock aquifers have been providing potable groundwater for many regions of the world, but there still many unknowns about the storage capacity, transit times and flow paths under changing climate scenarios. In this on-going study we aim to understand the magnitude of groundwater storage and Inter-basin flow for water supply development and sustainable use on the island of Tobago, WI. Samples of springs, surface water and production wells were analyzed for the stable isotopes of water (H2O) and strontium (Sr), tritium(3H) and sulfur hexafluoride (SF6). The stable isotopes of water &#948;Dvsmow and &#948;18Ovsmow indicates that the groundwater in the northern region of the island is not hydrologically connected to the groundwater to the south because of their distinct D-excess signature.87Sr/86Sr and Na-normalized strontium concentrations produces five possible mixing lines which radially increase from the lowest based value of 87Sr/86Sr ~ 0.70396 and Na/Sr (mg/L) ~0.00652. In detail, the maximum values of each line represent: extremes in Na concentration 87Sr/86Sr 0.70576 and Sr/Na 0.0008 mg/L, the groundwater to seawater mixing line87Sr/86Sr 0.70506 and Sr/Na 0.0023 mg/L, the precipitation to rock equilibration mixing line 87Sr/86Sr 0.70506 and Sr/Na 0.0023 mg/L, water located in silicate rocks to carbonate rocks mixing 87Sr/86Sr 0.70871 and Sr/Na 0.0085 mg/L, and wells that were once affected by seawater intrusion 87Sr/86Sr 0.70563 and Sr/Na 0.0692 mg/L.Tritium results range from 0.02 to 0.60 TU and calculations suggest that wells contain a range of 2 to 44% modern groundwater. When compared to other islands at similar latitudinal locations, Tobago&#8217;s groundwater presents the lowest mean and median tritium values even though it is the closest to the equator. Basin flux and effective porosity were calculated for the 10 wells using the apparent age obtained from these results under the assumption of piston flow. It was found that all watershed volumes were magnitudes of orders larger than the sub-basins where the wells were located ranging between 0.09 km3 to 8.23 km3. Basin Flux and effective porosity also contain large range differences 1.40 *105 m3/yr to 9.93 *106 m3/yr, and 0.014 to 0.094, respectively.This results also suggest that the groundwater in the southern regions of the island contains the oldest water with one well sample >60 years. SF6 results reflect similar ages except for 3 wells samples which are suspected to be contaminated by excess air. This novel discovery illustrates that small, fractured rock island aquifers can possess structural complexities that lead to older groundwater ages and variances in basin characteristics.&#160;

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Effects of compression during formation on the microstructure of composite hydroxylapatite/plaster implants for bone reconstruction

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100105813 ◽

1988 ◽

Vol 46 ◽

pp. 750-751

Author(s):

J. Hanker ◽

K. Cowden ◽

R. Noecker ◽

P. Yates ◽

N. Georgiade ◽

...

Keyword(s):

Cosmetic Surgery ◽

Glass Plate ◽

Surgical Reconstruction ◽

Equal Weight ◽

Sintered Ceramic ◽

Setting Times ◽

Excess Water ◽

Mixture Prior ◽

Mechanical Strengths ◽

Calcium Sulfate Hemihydrate

Composites of plaster of Paris (PP) and hydroxylapatite (HA) particles are being applied for the surgical reconstruction of craniofacial bone defects and for cosmetic surgery. Two types of HA particles are being employed, the dense sintered ceramic (DHA) and the porous, coralline hydroxylapatite (PHA) particles. Excess water is expressed out of the moistened HA/PP mixture prior to implantation and setting by pressing it in a non-tapered syringe against a glass plate. This results in implants with faster setting times and greater mechanical strengths. It was therefore of interest to compare samples of the compressed versus noncompressed mixtures to see whether or not any changes in their microstructure after setting could be related to these different properties.USG Medical Grade Calcium Sulfate Hemihydrate (which has the lowest mortar consistency of any known plaster) was mixed with an equal weight of Interpore 200 particles (a commercial form of PHA). After moistening with a minimum amount of water, disc-shaped noncompressed samples were made by filling small holes (0.339 in. diameter x 0.053 in. deep) in polypropylene molds with a microspatula.

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