scholarly journals GIS-based, python modeling of the spatial and temporal distribution of water on the landscape for wetlands decision making

2020 ◽  
Author(s):  
◽  
Zhentao Wang
Keyword(s):  
Decision Making ◽  
Surface Water ◽  
Water Balance ◽  
Water Surface ◽  
Overland Flow ◽  
Flow Direction ◽  
Water Volume ◽  
Small Scale ◽  
Time Step ◽  
Simulated Precipitation

Wetlands provide many benefits for humans and the natural environment, but land use changes have reduced their number and areal extent. Interest has grown in examining surface water distribution both spatially and temporally, which help to determine those locations for which there is the greatest priority for wetland preservation or mitigation. This research first proposes a methodology to support that examination through the application of open channel hydraulics principles to flow over a landscape. The methodology, implemented through a Python script, automatically extracts landscape characteristics from a DEM and calculates hydraulic parameters. The parameters are used to determine water surface profiles using the Modified Euler's method. Multiple tests show that the script accurately produces profiles of flow between wetlands over a landscape. Such determinations are the first step in understanding where water will exist on the surface and where there may be infiltration to support wetland functions. Furthermore, a water balance methodology (where water will exist, how much will be there and for what period of time) is developed and demonstrated that focuses on small depressions, as locations where conservation efforts to create or regenerate wetlands may be achievable. Integral to this analysis is a detailed treatment of depressions in the landscape. Utilizing a digital elevation model, the methodology incorporates a cell-by-cell analysis to appropriately capture small-scale processes. Instead of treating these vital depressions as errors or being insignificant to the water balance calculations, they are retained. Flow direction is dynamically determined by the land surface and water characteristics. With potentially shallow flow in depressions, the use of Manning's equation incorporates stratified flow where differing values of Manning's n describe flow through and above vegetation. This real-time overland runoff model based on a short time step is implemented through a Python code using ArcGIS. Exercises on an artificial DEM with simulated precipitation demonstrate the ability of the model to accurately represent hydraulics principles. Simulations of two field sites over a period of a year, and incorporating precipitation, infiltration and evapotranspiration, demonstrate the ability to track water surface locations and extents with an accuracy necessary for decision making. Additionally, this research optimizes the Green Ampt infiltration model which allows for the calculation of infiltration rates with unsteady rainfall and then couples this Modified Green Ampt (MGA) model with a previously developed Dynamic Flow Direction (DFD) model to simulate overland flow. To test the accuracy of the improvements, results show shorter times to ponding, smaller total infiltration at the time of ponding and larger total infiltration with this Modified Green Ampt (MGA) model as compared with the results with a Traditional Green Ampt (TGA) model. Additionally, coupled with the DFD model, the MGA model takes surface water movement into consideration. The total water volume on the landscape with MGA is less than predicted by the TGA. Additionally, the inundation area is deeper than 0.05 m with MGA and is also smaller than the result with the TGA.

scholarly journals A journey of a thousand miles begins with one small step – human agency, hydrological processes and time in socio-hydrology

2013 ◽  
Vol 10 (11) ◽  
pp. 14265-14304 ◽  
Author(s):  
M. W. Ertsen ◽  
J. T. Murphy ◽  
L. E. Purdue ◽  
T. Zhu
Keyword(s):  
Decision Making ◽  
Social Action ◽  
Human Agency ◽  
The Other ◽  
Social Structures ◽  
Small Scale ◽  
Small Step ◽  
Time Step ◽  
Human Decision ◽  
Day To Day Operations

Abstract. When simulating social action in modeling efforts, as in socio-hydrology, an issue of obvious importance is how to ensure that social action by human agents is well-represented in the analysis and the model. Generally, human decision-making is either modeled on a yearly basis or lumped together as collective social structures. Both responses are problematic, as human decision making is more complex and organizations are the result of human agency and cannot be used as explanatory forces. A way out of the dilemma how to include human agency is to go to the largest societal and environmental clustering possible: society itself and climate, with time steps of years or decades. In the paper, the other way out is developed: to face human agency squarely, and direct the modeling approach to the human agency of individuals and couple this with the lowest appropriate hydrological level and time step. This approach is supported theoretically by the work of Bruno Latour, the French sociologist and philosopher. We discuss irrigation archaeology, as it is in this discipline that the issues of scale and explanatory force are well discussed. The issue is not just what scale to use: it is what scale matters. We argue that understanding the arrangements that permitted the management of irrigation over centuries, requires modeling and understanding the small-scale, day-to-day operations and personal interactions upon which they were built. This effort, however, must be informed by the longer-term dynamics as these provide the context within which human agency, is acted out.

Evaluating the effects of climate change for groundwater quantitative status in Denmark

2020 ◽  
Author(s):  
Annesofie Jakosben ◽  
Hans Jørgen Henriksen ◽  
Ernesto Pasten-Zapata ◽  
Torben Sonnenborg ◽  
Lars Troldborg
Keyword(s):  
Climate Change ◽  
Surface Water ◽  
Water Balance ◽  
Overland Flow ◽  
Future Climate Change ◽  
Historical Period ◽  
Climate Projections ◽  
Monitoring Networks ◽  
Groundwater Levels ◽  
Ecological Flow

<p>By use of transient and distributed groundwater-surface water flow models, simulated time series of stream discharge and groundwater level for monitoring networks, groundwater bodies and river reaches have been analysed for a historical period and four different future scenarios toward 2100 in two large-scale catchments in Denmark. The purpose of the climate scenarios has been to qualify the existing knowledge on how future climate change most likely will impact hydrology, groundwater status and Ecological Quality Elements (EQR- Ecological flow in rivers). Another purpose has been to identify whether foreseen climate changes will be detected by the surface water and groundwater monitoring networks, and to which degree the River Basin Management Plan measures for supporting the goal of good quantitative status are robust to the projected changes in water balance and ecological flow. The developed hydrological models were run with climate inputs based on selected RCP4.5 and RCP8.5 climate model runs (RCP8.5 wet, median, dry and RCP4.5 median). Changes in groundwater quantitative status and ecological flow metrics were calculated based on 30-year model runs driven by RCP8.5 for 2071-2100 (RCP4.5 for 2041-70) and compared to 1981-2010.</p><p>Overall the four scenarios results in very significant water balance changes with increased precipitation: 3% to 27%, evapotranspiration: 6% to 17%, groundwater recharge: 0% to 49%, drainage flow: 0% to 71%, baseflow: 0% to 31% and overland flow: 16% to 281%. For one catchment an increase in abstraction of 23% to 171% due to an increase in irrigation demand by 36% to 113% is foreseen. The results have wide implications for groundwater flooding risks, quantitative status and ecological flow metrics. Most sensitive is changes in ecological flow conditions in rivers for fish, showing a relative high probability for decreased state for 10-20% of the reaches for the RCP8.5 wet and dry scenarios due to more extreme hydrological regimes toward 2071-2100. Maximum monthly runoff is increased for winter months by 100% for RCP8.5 wet and median scenarios and around 10% for RCP8.5 dry scenario. Annual maximum daily flows is simulated to increase by up to a factor of five, and late summer low flows decreased.</p><p>Impacts on groundwater levels and water balances of groundwater bodies will be significant, with increased seasonal fluctuations and also increased maximum and decreased minimum groundwater levels for 30 year periods for 2071-2100 compared to 1981-2010.</p><p>More rain, both when we look back on historical data and when we look forward with latest climate projections will result in more frequent flooding from groundwater and streams in the future. At the same time, the temperature and thus evapotranspiration rises. This means that in the long term we will have increased challenges with drought and increased irrigation demands on sandy soils while evapotranspiration will also increase on the clayey soils. This will result in greater fluctuation in the flow and groundwater levels between winters and summers, and between wet and dry years, challenging sustainable groundwater abstraction and maintaining good quantitative status of groundwater bodies.</p>

scholarly journals Assessing the capabilities of the Surface Water and Ocean Topography (SWOT) mission for large lake water surface elevation monitoring under different wind conditions

2020 ◽  
Vol 24 (12) ◽  
pp. 5985-6000
Author(s):  
Jean Bergeron ◽  
Gabriela Siles ◽  
Robert Leconte ◽  
Mélanie Trudel ◽  
Damien Desroches ◽  
...  
Keyword(s):  
Surface Water ◽  
Water Surface ◽  
Management Strategies ◽  
Water Volume ◽  
Spatial And Temporal Variability ◽  
Large Lakes ◽  
Spatial Coverage ◽  
Lake Hydrodynamics ◽  
Ocean Topography ◽  
Set Up

Abstract. Lakes are important sources of freshwater and provide essential ecosystem services. Monitoring their spatial and temporal variability, and their functions, is an important task within the development of sustainable water management strategies. The Surface Water and Ocean Topography (SWOT) mission will provide continuous information on the dynamics of continental (rivers, lakes, wetlands and reservoirs) and ocean water bodies. This work aims to contribute to the international effort evaluating the SWOT satellite (2022 launch) performance for water balance assessment over large lakes (e.g., >100 km2). For this purpose, a hydrodynamic model was set up over Mamawi Lake, Canada, and different wind scenarios on lake hydrodynamics were simulated. The derived water surface elevations (WSEs) were compared to synthetic elevations produced by the Jet Propulsion Laboratory (JPL) SWOT high resolution (SWOT-HR) simulator. Moreover, water storages and net flows were retrieved from different possible SWOT orbital configurations and synthetic gauge measurements. In general, a good agreement was found between the WSE simulated from the model and those mimicked by the SWOT-HR simulator. Depending on the wind scenario, errors ranged between approximately −2 and 5 cm for mean error and from 30 to 70 cm root mean square error. Low spatial coverage of the lake was found to generate important biases in the retrievals of water volume or net flow between two satellite passes in the presence of local heterogeneities in WSE. However, the precision of retrievals was found to increase as spatial coverage increases, becoming more reliable than the retrievals from three synthetic gauges when spatial coverage approaches 100 %, demonstrating the capabilities of the future SWOT mission in monitoring dynamic WSE for large lakes across Canada.

Evaluation of Oil Fate and Exposure from a Deep Water Blowout With and Without Subsea Dispersant Injection Treatment as Well as Traditional Response Activities

2017 ◽  
Vol 2017 (1) ◽  
pp. 362-382 ◽  
Author(s):  
Deborah French-McCay ◽  
Deborah Crowley ◽  
Jill Rowe
Keyword(s):  
Surface Water ◽  
Deep Water ◽  
Water Surface ◽  
Oil And Gas ◽  
Early Life History ◽  
Water Volume ◽  
Response Options ◽  
Degradation Rates ◽  
Order Of Magnitude ◽  
Wind Currents

ABSTRACT The goals of subsea dispersant injection (SSDI) into a deep water oil and gas blowout are to increase effectiveness of dispersant treatment over that achievable at the water surface; decrease the volume of oil that surfaces; reduce human and wildlife exposure to volatile organic compounds (VOCs); disperse the oil over a large water volume at depth; enhance biodegradation; and reduce surface, nearshore and shoreline exposure to floating and surface-water entrained/dissolved oil. Potential tradeoffs include increased water column and benthic resource exposures to oil at depth. In order to better understand the implications of SSDI use, we modeled a hypothetical blowout in the northern Gulf of Mexico to predict oil fate and compare the environmental exposure for no intervention to various response options (i.e., mechanical recovery, in-situ burning (ISB), surface dispersant application, and SSDI). Probabilistic modeling was used to evaluate the influence of variable metocean conditions (i.e., wind, currents, temperature). The results showed that even with a substantial capacity of equipment applied, mechanical and ISB removed only a small fraction of the oil that would otherwise be floating or evaporate. Compared to cases without use of SSDI, SSDI reduced the size of oil droplets by an order of magnitude, substantially decreased the amount of oil on the water surface and on the shoreline, increased dissolution and degradation rates of hydrocarbons at depth, increased weathering rate of rising oil such that floating oil contained much lower content of soluble and semi-soluble hydrocarbons, decreased surface water concentrations of dissolved hydrocarbons, and decreased VOC emissions to the atmosphere and, therefore, reduced human and wildlife exposures to VOCs. The tradeoff was that with SSDI there was greater exposure to hydrocarbons in deep water. However, densities of biota are much lower in deep water than near the water surface, where sensitive early life history stages of fish and invertebrates are most abundant. This approach provides decision makers with quantitative environmental exposures with which they may evaluate risk tradeoffs regarding appropriate response strategies for mitigating impacts from oil and gas released during a deep water blowout.

scholarly journals A journey of a thousand miles begins with one small step – human agency, hydrological processes and time in socio-hydrology

2014 ◽  
Vol 18 (4) ◽  
pp. 1369-1382 ◽  
Author(s):  
M. W. Ertsen ◽  
J. T. Murphy ◽  
L. E. Purdue ◽  
T. Zhu
Keyword(s):  
Decision Making ◽  
Social Action ◽  
Human Agency ◽  
Social Structures ◽  
Small Scale ◽  
Bruno Latour ◽  
Small Step ◽  
Time Step ◽  
Human Decision ◽  
Day To Day Operations

Abstract. When simulating social action in modeling efforts, as in socio-hydrology, an issue of obvious importance is how to ensure that social action by human agents is well-represented in the analysis and the model. Generally, human decision-making is either modeled on a yearly basis or lumped together as collective social structures. Both responses are problematic, as human decision-making is more complex and organizations are the result of human agency and cannot be used as explanatory forces. A way out of the dilemma of how to include human agency is to go to the largest societal and environmental clustering possible: society itself and climate, with time steps of years or decades. In the paper, another way out is developed: to face human agency squarely, and direct the modeling approach to the agency of individuals and couple this with the lowest appropriate hydrological level and time step. This approach is supported theoretically by the work of Bruno Latour, the French sociologist and philosopher. We discuss irrigation archaeology, as it is in this discipline that the issues of scale and explanatory force are well discussed. The issue is not just what scale to use: it is what scale matters. We argue that understanding the arrangements that permitted the management of irrigation over centuries requires modeling and understanding the small-scale, day-to-day operations and personal interactions upon which they were built. This effort, however, must be informed by the longer-term dynamics, as these provide the context within which human agency is acted out.

The coastal El Niño-Event of 2017 in Ecuador and Peru - a weather Radar analysis

2020 ◽  
Author(s):  
Rütger Rollenbeck ◽  
Andreas Fries ◽  
Jörg Bendix ◽  
Johanna Orellana-Alvear ◽  
Mario Guallpa ◽  
...  
Keyword(s):  
Flow Direction ◽  
Regional Scale ◽  
Coastal Region ◽  
Weather Radar ◽  
Sea Breeze ◽  
Small Scale ◽  
Central Pacific ◽  
Time Step ◽  
Weather Patterns ◽  
Weather Radars

<p>The arid coastal region of Ecuador and Peru belong to the regions experiencing the strongest impact of the El-Niño-Phenomenon. In spite of neutral to cold conditions after the decaying 2015/16 El Niño, unexpected by internationl scientists and local authorities alike, in 2017 the region was hit by torrential rain falls causing floodings, erosion and landslides with many fatalities and significant damage to infrastructure.</p><p>RadarNetSur (www.radarnetsur.de), initiated in 2012 to 2015 forms the first weather radar network in that region and was capable of monitoring the development of the 2017 event up to its culmination, providing insight into rainfall distribution (resolution of 500 m) on a 5-minute time step. The network consists of 3 X-Band-scanning weather Radars with a range of 60 to 100 km, thus covering 80000 km² from 2° S to 4°S. In 2019 the network was extended far into Peru with a new system in Piura.</p><p>We present results of the analysis of the event and compare it to the conditions in the years 2014, 2015 and 2016, to point out spatial patterns and process dynamics, which led to this unusual coastal El-Niño during central Pacific La-Niña conditions. Apparently, the isolated warming of the Niño 1+2 regions off the coast was the main driver of these strong rainfalls, but the local expression of weather patterns is shaped by topographic conditions interacting with the synoptical situation (West wind bursts) and small-scale circulation systems like the sea-breeze and mountain-valley breeze. Most intense rainfall is associated with disturbances in the divergence field which are intensified by changes of the synoptical flow direction.   We assume, that either the conventional understanding of the ENSO-impact on the regional scale is insufficient, or, the ENSO-phenomenon is slowly transitioning into a more complex behavior.</p>

scholarly journals Evaluation of AMIP II Global Climate Model Simulations of the Land Surface Water Budget and Its Components over the GEWEX-CEOP Regions

2007 ◽  
Vol 8 (3) ◽  
pp. 304-326 ◽  
Author(s):  
P. Irannejad ◽  
A. Henderson-Sellers
Keyword(s):  
Surface Water ◽  
Water Balance ◽  
Land Surface ◽  
Water Budget ◽  
Global Climate Model ◽  
Atmospheric Model ◽  
Water Balance Components ◽  
Land Surface Water ◽  
Simulated Precipitation ◽  
Basin Scale

Abstract The land surface water balance components simulated by 20 atmospheric global circulation models (AGCMs) participating in phase II of the Atmospheric Model Intercomparison Project (AMIP II) are analyzed globally and over seven Global Energy and Water Cycle Experiment Coordinated Enhanced Observing Period basins. In contrast to the conclusions from analysis of AMIP I, the results presented here suggest that the group average of available AGCMs does not outperform all individual AGCMs in simulating the surface water balance components. Analysis shows that the available reanalysis products are not appropriate for evaluation of AGCMs’ simulated land surface water components. The worst simulation of the surface water budget is in the Murray–Darling, the most arid basin, where all the reanalyses and seven of the AGCMs produce a negative surface water budget, with evaporation alone exceeding precipitation and soil moisture decreasing over the whole AMIP II period in this basin. The spatiotemporal correlation coefficients between observed and AGCM-simulated runoff are smaller than those for precipitation. In almost all basins (except for the two most arid basins), the spatiotemporal variations of the AGCMs’ simulated evaporation are more coherent and agree better with observations, compared to those of simulated precipitation. This suggests that differences among the AGCMs’ surface water budget predictions are not solely due to model-generated precipitation differences. Specifically, it is shown that different land surface parameterization schemes partition precipitation between evaporation and runoff differently and that this, in addition to the predicted differences in atmospheric forcings, is responsible for different predictions of basin-scale water budgets. The authors conclude that the selection of a land surface scheme for an atmospheric model has significant impacts on the predicted continental and basin-scale surface hydrology.

scholarly journals Flow analysis with WaSiM-ETH – model parameter sensitivity at different scales

2006 ◽  
Vol 9 ◽  
pp. 73-77 ◽  
Author(s):  
J. Cullmann ◽  
V. Mishra ◽  
R. Peters
Keyword(s):  
Water Balance ◽  
Overland Flow ◽  
Flow Analysis ◽  
Flood Forecasting ◽  
Special Focus ◽  
Time Step ◽  
Space Resolution ◽  
Process Dynamics ◽  
Time Calculation ◽  
Daily Time Step

Abstract. WaSiM-ETH (Gurtz et al., 2001), a widely used water balance simulation model, is tested for its suitability to serve for flow analysis in the context of rainfall runoff modelling and flood forecasting. In this paper, special focus is on the resolution of the process domain in space as well as in time. We try to couple model runs with different calculation time steps in order to reduce the effort arising from calculating the whole flow hydrograph at the hourly time step. We aim at modelling on the daily time step for water balance purposes, switching to the hourly time step whenever high-resolution information is necessary (flood forecasting). WaSiM-ETH is used at different grid resolutions, thus we try to become clear about being able to transfer the model in spatial resolution. We further use two different approaches for the overland flow time calculation within the sub-basins of the test watershed to gain insights about the process dynamics portrayed by the model. Our findings indicate that the model is very sensitive to time and space resolution and cannot be transferred across scales without recalibration.

Managing the impacts of mining on Ghana’s water resources from a legal perspective

2018 ◽  
Vol 1 (3) ◽  
pp. 156-165 ◽  
Author(s):  
Nasirudeen Abdul Fatawu
Keyword(s):  
Surface Water ◽  
Water Resources ◽  
Environmental Protection Agency ◽  
Large Scale ◽  
Small Scale ◽  
Mining Activities ◽  
Protection Agency ◽  
Environmental Laws ◽  
Mining Areas ◽  
Legal Perspective

Recent floods in Ghana are largely blamed on mining activities. Not only are lives lost through these floods, farms andproperties are destroyed as a result. Water resources are diverted, polluted and impounded upon by both large-scale minersand small-scale miners. Although these activities are largely blamed on behavioural attitudes that need to be changed, thereare legal dimensions that should be addressed as well. Coincidentally, a great proportion of the water resources of Ghana arewithin these mining areas thus the continual pollution of these surface water sources is a serious threat to the environmentand the development of the country as a whole. The environmental laws need to be oriented properly with adequate sanctionsto tackle the impacts mining has on water resources. The Environmental Impact Assessment (EIA) procedure needs to bestreamlined and undertaken by the Environmental Protection Agency (EPA) and not the company itself.

HOUSEHOLD WATER BALANCE AND ASSESSMENT OF WATER VOLUME FOR IRRIGATION IN AGRO LANDSCAPES OF THE KYZYLSU-YUZHNAYA BASIN

2020 ◽  
pp. 102-109
Author(s):  
D.KH. DOMULLODZHANOV ◽  
◽  
R. RAHMATILLOEV
Keyword(s):  
Water Balance ◽  
River Basin ◽  
Water Use ◽  
Storage Systems ◽  
Low Cost ◽  
Field Studies ◽  
Water Volume ◽  
Land Productivity ◽  
Household Water ◽  
And Storage

The article presents the results of the field studies and observations that carried out on the territory of the hilly, low-mountain and foothill agro landscapes of the Kyzylsu-yuzhnaya (Kyzylsu-Southern) River Basin of Tajikistan. Taking into account the high-altitude location of households and the amount of precipitation in the river basin, the annual volumes of water accumulated with the use of low-cost systems of collection and storage of precipitation have been clarified. The amount of water accumulated in the precipitation collection and storage systems has been established, the volume of water used for communal and domestic needs,the watering of livestock and the amount of water that can be used to irrigate crops in the have been determined. Possible areas of irrigation of household plots depending on the different availability of precipitation have been determined. It has been established that in wet years (with precipitation of about 10%) the amount of water collected using drip irrigation will be sufficient for irrigation of 0.13 hectares, and in dry years (with 90% of precipitation) it will be possible to irrigate only 0.03 ha of the household plot. On the basis of the basin, the total area of irrigation in wet years can be 4497 ha, and in dry years only 1087 ha. Taking into account the forecasts of population growth by 2030 and an increase in the number of households, the total area of irrigation of farmlands in wet years may reach 5703 hectares,and in dry years – 1379 hectares. Growing crops on household plots under irrigation contributes to a significant increase in land productivity and increases the efficiency of water use of the Kyzylsu-yuzhnaya basin.

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