This document summarizes optimization techniques for managing saltwater intrusion in coastal aquifers. It begins with an introduction to the problem of saltwater intrusion caused by pumping fresh water from coastal aquifers. It then presents the mathematical model and equations used to describe water flow. Three types of coastal aquifers are described along with analytical solutions. An optimization algorithm called ALOPEX is introduced for determining optimal well placement and pumping rates. Numerical simulations are shown applying ALOPEX to sample aquifers with 2 and 5 wells. Sensitivity analysis is also presented by varying pumping rates, recharge rates, and ambient water discharge.
Hydrological Application of Remote – Sensing and GIS for Handling of Excess R...IDES Editor
A GIS based hydrological analysis has been carried
out to explore the possibility of diverting storm runoff
generated from the upper catchment safely through a canal
system constructed at the foothill to avoid flooding at
downstream. The study area consisted of Kalapahar-Udyachal
hills (5.38 km sq) in the Kahilipara- Odalbakra area, situated
in the city of Guwahati, Assam. The Digital Elevation Model
(DEM) of the study area was developed from the Survey of
India(SOI) toposheet (1972) using Arcgis software. Watershed
delineation and derivation of required topographic parameters
for for calculating the peak discharge from different
watersheds were done with the help of the generated DEM.
Based on the hydrological analysis, means of safe diversion
of runoff water from hillocks was found out and canal
design of varying geometry capable of handling the peak
discharge suggested.
Sustainable flood risk management and its various techniques are discussed here with the help of a case study. Also, this presentation discusses the effectiveness of detention ponds in urban flood management.
Hydrological Application of Remote – Sensing and GIS for Handling of Excess R...IDES Editor
A GIS based hydrological analysis has been carried
out to explore the possibility of diverting storm runoff
generated from the upper catchment safely through a canal
system constructed at the foothill to avoid flooding at
downstream. The study area consisted of Kalapahar-Udyachal
hills (5.38 km sq) in the Kahilipara- Odalbakra area, situated
in the city of Guwahati, Assam. The Digital Elevation Model
(DEM) of the study area was developed from the Survey of
India(SOI) toposheet (1972) using Arcgis software. Watershed
delineation and derivation of required topographic parameters
for for calculating the peak discharge from different
watersheds were done with the help of the generated DEM.
Based on the hydrological analysis, means of safe diversion
of runoff water from hillocks was found out and canal
design of varying geometry capable of handling the peak
discharge suggested.
Sustainable flood risk management and its various techniques are discussed here with the help of a case study. Also, this presentation discusses the effectiveness of detention ponds in urban flood management.
Application of the random walk theory for simulation of flood hazzards jeddah...Amro Elfeki
Simulation of Urban Flooding by Diffusive Wave Model: Jeddah Flood 2009 Case Study. Proceeding of 1st International Geomatics Symposium in Saudi Arabia in collaboration with University of Florida and INSA Strasbourg: Geomatics Technologies in the City, 10-11 May 2011, A. Mohamed (Ed.), pp. 119-123.
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IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
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Why plan for growth and change, when it seems so much easier to simply react?
When there is a distinct and shared vision for your community - when residents, businesses and local government anticipate a sustainable town with cohesive and thriving neighborhoods - you have the power to conserve your beautiful natural spaces, enhance your existing downtown or Main Street, enable rural areas to be productive and prosperous, and save money through efficient use of existing infrastructure.
This is the dollars and sense of smart growth.
Success is clearly visible in Maine, from the creation of a community-built senior housing complex and health center in Fort Fairfield to conservation easements creating Forever Farms to Rockland's revitalized downtown. Communities have options. We have the power to manage our own responses to growth and change.
After all, “Planning is a process of choosing among those many options. If we do not choose to plan, then we choose to have others plan for us.” - Richard I. Winwood
And in the end, this means that our children and their children will choose to make Maine home and our economy will provide the opportunities to do so.
The Summit offers you a wonderful opportunity to be a part of the transformative change in Maine that we’ve seen these gatherings produce. We encourage you to consider the value of being actively involved in growing Maine’s economy and protecting the reasons we choose to live here.
Morphometric analysis of a vrishabhavathi sub watershed upstream side of gali...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Application of the random walk theory for simulation of flood hazzards jeddah...Amro Elfeki
Simulation of Urban Flooding by Diffusive Wave Model: Jeddah Flood 2009 Case Study. Proceeding of 1st International Geomatics Symposium in Saudi Arabia in collaboration with University of Florida and INSA Strasbourg: Geomatics Technologies in the City, 10-11 May 2011, A. Mohamed (Ed.), pp. 119-123.
Evaluation of Standar & Regional Satellite Chlorophyll-a Algorithms for MODIS...Anisa Aulia Sabilah
Review Jurnal Penginderaan Jauh Sinar Tampak "Evaluation of Standar & Regional Satellite Chlorophyll-a Algorithms for MODIS in the Bohai & Yellow Seas, China" oleh Wang et al. (2019)
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Sea level rise and storm surge tools and datasets supporting Municipal Resili...GrowSmart Maine
Why plan for growth and change, when it seems so much easier to simply react?
When there is a distinct and shared vision for your community - when residents, businesses and local government anticipate a sustainable town with cohesive and thriving neighborhoods - you have the power to conserve your beautiful natural spaces, enhance your existing downtown or Main Street, enable rural areas to be productive and prosperous, and save money through efficient use of existing infrastructure.
This is the dollars and sense of smart growth.
Success is clearly visible in Maine, from the creation of a community-built senior housing complex and health center in Fort Fairfield to conservation easements creating Forever Farms to Rockland's revitalized downtown. Communities have options. We have the power to manage our own responses to growth and change.
After all, “Planning is a process of choosing among those many options. If we do not choose to plan, then we choose to have others plan for us.” - Richard I. Winwood
And in the end, this means that our children and their children will choose to make Maine home and our economy will provide the opportunities to do so.
The Summit offers you a wonderful opportunity to be a part of the transformative change in Maine that we’ve seen these gatherings produce. We encourage you to consider the value of being actively involved in growing Maine’s economy and protecting the reasons we choose to live here.
Morphometric analysis of a vrishabhavathi sub watershed upstream side of gali...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Efficiency of vertical drains using finite element method may 2017Dr Mazin Alhamrany
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Landslides of any type, and particularly soil slips, pose a great threat in mountainous and steep terrain environ- ments. One of the major triggering mechanisms for slope failures in shallow soils is the build-up of soil pore water pressure resulting in a decrease of effective stress. However, infiltration may have other effects both before and after slope failure. Especially, on steep slopes in shallow soils, soil slips can be triggered by a rapid drop in the apparent cohesion following a decrease in matric suction when a wetting front penetrates into the soil without generating positive pore pressures. These types of failures are very frequent in pre-alpine and alpine landscapes. The key factor for a realistic prediction of rainfall-induced landslides are the interdependence of shear strength and suction and the monitoring of suction changes during the cyclic wetting (due to infiltration) and drying (due to percolation and evaporation) processes. The non-unique relationship between suction and water content, expressed by the Soil Water Retention Curve, results in different values of suction and, therefore, of soil shear strength for the same water content, depending on whether the soil is being wetted (during storms) or dried (during inter-storm periods). We developed a physically based distributed in space and continuous in time model for the simulation of the hydrological triggering of shallow landslides at scales larger than a single slope. In this modeling effort particular weight is given to the modeling of hydrological processes in order to investigate the role of hydrologi- cal triggering mechanisms on soil changes leading to slip occurrences. Specifically, the 3D flow of water and the resulting water balance in the unsaturated and saturated zone is modeled using a Cellular Automata framework. The infinite slope analysis is coupled to the hydrological component of the model for the computation of slope stability. For the computation of the Factor of Safety a unified concept for effective stress under both saturated and unsaturated conditions has been used (Lu Ning and Godt Jonathan, WRR, 2010). A test case of a serious landslide event in Switzerland is investigated to assess the plausibility of the model and to verify its perfomance.
In this study the kinematic wave equation has been solved numerically using the modified Lax
explicit finite difference scheme (MLEFDS) and used for flood routing in a wide prismatic channel and a nonprismatic
channel. Two flood waves, one sinusoidal wave and one exponential wave, have been imposed at the
upstream boundary of the channel in which the flow is initially uniform. Six different schemes have been
introduced and used to compute the routing parameter, the wave celerity c. Two of these schemes are based on
constant depth and use constant celerity throughout the computation process. The rest of the schemes are based
on local depths and give celerity dependent on time and space. The effects of the routing parameter c on the
travel time of flood wave, the subsidence of the flood peak and the conservation flood flow volume have been
studied. The results seem to indicate that there is a minimal loss/gain of flow volume whatever the scheme is.
While it is confirmed that neither of the schemes is 100% volume conservative, it is found that the scheme
Kinematic Wave Model-2 (KWM-II) gives the most accurate result giving only 0.1% error in perspective of
volume conservation. The results obtained in this study are in good qualitative agreement with those obtained in
other similar studies.
Flooding areas of Ofanto river using advanced topographic and hydraulic appro...Lia Romano
6th International Symposium on Geo-information for Disaster Management (Turin)
POSTER
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Apulia Basin Authority (AdBP) is actually carrying out an advanced and complex study for evaluating flooding areas
of downstream reach of Ofanto, one of the most important river in Southern Italy. The performed analysis is strictly
related to a reliable definition of the hydraulic risk map in order to plan efficient hazard management actions. Due
to the geo-morphological characteristics of the selected river branch – that presents a length of about 36 km from
the Roman bridge, close to Canosa city, to the sea outfall –- this activity represents an interesting case study for
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scanning (LIDAR), which generates 1 m cell-size Digital Surface Model (DSM) and Digital Terrain Model (DTM), that
were integrated with high-resolution digital orthophotos. The hydraulic simulation was developed adopting a mixed
1D/2D scheme, where one-dimensional model within the levees and two-dimensional model outside were used.
Simplified model for estimating friction factor distribution within the floodplain area was adopted.
Modeling dispersion under unsteady groundwater flow conditionsAmro Elfeki
This presentation is for and MSc Student working on some of the projects at TU Delft. The thesis title is: Modeling dispersion under unsteady groundwater flow conditions.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Analytical modelling of groundwater wells and well systems: how to get it r...Anton Nikulenkov
Aquifer tests are probably the most widely used methods to obtain hydrogeological properties that are vital for any mine dewatering or environmental impact assessments. Numerous softwares and methods currently exist that provide quick and easy tests interpretation by fitting theoretical and measured drawdown curves. However, misinterpreting a-priory groundwater concepts and not accounting correctly for such factors as skin-effect, well storage or partial penetration may result in hydraulic conductivity errors by several hundred precents. As illustrated by case studies from WA, both numerical and analytical models generally suffer from non-uniqueness that can be overcome by understanding a-priory groundwater concepts and implementing them appropriately into the interpretation algorithms.
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See how to accelerate model training and optimize model performance with active learning
Learn about the latest enhancements to out-of-the-box document processing – with little to no training required
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Length: 30 minutes
Session Overview
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- What are the benefits of integrating InfluxDB and Grafana into the load testing stack?
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Optimization techniques for a model problem of saltwater intrusion in coastal aquifers
1. Optimization techniques for a model problem of saltwater
intrusion in coastal aquifers
1
Applied Math and Computers Lab
Department of Sciences
Technical University of Crete
27/7/2013
P.N. Stratis, E.P. Papadopoulou, M.S. Zakynthinaki
and Y.G. Saridakis
This research has been co-financed by the European Union (European Social
Fund – ESF) and Greek national funds through the Operational Program
"Education and Lifelong Learning" of the National Strategic Reference
Framework (NSRF) - Research Funding Program: THALIS. Investing in
knowledge society through the European Social Fund.
2. Presentation contents
• Part 1. Saltwater intrusion
• Part 2. Mathematical approach-model equations
• Part 3. Types of coastal freshwater aquifers
• Part 4. Pumping optimization methods
• Part 5. Numerical simulations
227/7/2013
3. Part 1. Saltwater intrusion
Basic description of the problem.
327/7/2013
4. The problem:
Rapidly increasing needs for fresh water in coastal areas and
islands, due to:
Population growth
Tourism
Agriculture needs
results to:
• Intensive pumping in freshwater aquifers, mostly during
summer months, beyond the tolerable limits of their natural
replenishment.
427/7/2013
5. Consequences:
• Decrease in freshwater table level in these areas.
• Sea water intrusion into the coastal aquifer.
• Mixing of fresh and salt water creates water quality problems.
• Wells of the area becoming unusable for water supply and
irritation.
• Negative economical impacts in these areas.
527/7/2013
6. There is a great need for developing pumping management
methodologies, in order to determine:
• the total volume of water that can be pumped from coastal aquifers,
while protecting the wells from saltwater intrusion.
• the optimal places where wells can be placed, in order to maximize
the non-risk pumping of fresh water.
• the max number of wells that can be distributed over the aquifer.
627/7/2013
7. Part 2. Mathematical approach-model equations
Presentation of the mathematical model simplifications
and equations, we use to describe the water flow inside
the aquifer.
727/7/2013
8. Model simplifications
Flow in coastal aquifers is a very complex process, because
• there exist more than one mixing fluid phases,
• fluid density depends on the unknown concentrations,
• there exist a great spatial variability of hydraulic parameters
inside the region of the aquifer.
So, model simplifications are needed, in order to provide
reasonable approximate predictions. The most common of them
are:
• Sharp Interface approximation,
• Ghyben-Herzberg equation.
827/7/2013
9. Sharp Interface approximation:
• There is no direct mixing of sea and fresh water inside the aquifer.
• There exists an Interface area, the movement and position of which
we are trying to study.
Ghyben-Herzberg equation:
, where
• We can use this equation only if the Interface area is practically
stabilized at some position, i.e. when the flow conditions approach
steady state.
927/7/2013
11. Parameters of the aquifer (distances)
• L: Length of the aquifer.
• B: Width of the aquifer.
• d: Height of the aquifer from its bottom to sea level.
• b(x,y): Freshwater depth from free surface to the Interface.
• ξ(x,y): Freshwater depth from the sea level to the Interface.
• hf(x,y): Freshwater piezometric head with reference to the bottom
of the aquifer.
1127/7/2013
12. Parameters of the aquifer (areas and water movement)
• τ: Points where the interface surface intersects the base of the
aquifer (Toes area).
• Q (m3/day): Pumping rates of the aquifer wells.
• Ν (mm/year): Water recharge distributed over the surface of the
aquifer (e.g. rain, rivers).
• Κ (m/day): Hydraulic conductivity.
• q (m2/day): Ambient horizontal discharge per unit width of the
aquifer.
1227/7/2013
13. Equations:
• Zone 1. Steady flow equation:
where hf = b.
• Zone 2. Steady flow equation:
where hf = b+d-ξ.
1327/7/2013
14. Following Strack[1976], we define the flow potential φ=φ(x,y)
as follows:
• Zone 1.
• Zone 2.
• Toes of interface area.
ξ = δ, hf = (1+δ)d and
1427/7/2013
15. The flow potential φ=φ(x,y) is a continuous and smooth function
across the boundary between zones 1 and 2 and satisfies the
differential equation:
with boundary conditions:
coast boundary (x=0): ξ=0, φ(0,y)=0
(i.e. at no flow boundaries the flow towards direction n
perpendicular to the boundary is 0).
1527/7/2013
16. If K, N, Q and the boundary conditions are known, the previous
equation can be solved for φ(x,y) using analytical or numerical
methods. Once φ(x,y) is determined, the interface surface can be
calculated as a function of φ, as follows:
• Zone 1.
z = 0, , for
• Zone 2.
, , for
1627/7/2013
17. Finally, the locus of the Toes of Interface area can be determined by
solving for xT, as a function of yT, the following nonlinear equation:
1727/7/2013
18. Part 3. Types of coastal freshwater aquifers
Presentation of three types of coastal freshwater aquifers,
with different sets of boundaries. Analytical solution of
flow potential φ=φ(x,y) for these aquifers.
1827/7/2013
20. Aquifer type A. Semi infinite dimensions.
Homogeneous aquifer bounded only on one side by the coastline.
• Analytical solution of flow potential
(Strack[1976], Cheng[2000]):
where (xj, yj), j=1,..,M are the coordinates of the wells.
2027/7/2013
22. Aquifer type Β. Infinite length.
Homogeneous aquifer bounded on the left side by the coastline,
with up and down impervious boundaries.
• Analytical solution of flow potential:
where (xj, yj), j=1,..,M are the coordinates of the wells.
2227/7/2013
24. Aquifer type C. Rectangular shape.
Homogeneous aquifer bounded on the left side by the coastline with
up, down and right impervious boundaries.
• Analytical solution of flow potential:
2427/7/2013
26. Part 4. Pumping optimization methods in coastal aquifers
Our goal is to achieve the maximum pumping rates of all the wells
inside the aquifer, without risking the saltwater contamination of
the wells, known as the Toe Constraint formulation.
2627/7/2013
27. AL.O.P.EX. method (ALgorithm Of Pattern EXtraction)
• Introduced by Harth και Tzanakou, Syracuse University, 1974.
• Stochastic optimization for adaptive correction of atmospheric
distortion in astronomical observation, M. Zakynthinaki, PhD Thesis,
Chania, 2001.
• Stochastic optimization algorithm.
• Control (cost-profit) function f=f(x1,x2,x3,x4,..,xn).
• Goal: Maximize or minimize the control function.
• Local extrema can be avoided by the use of some kind of noise.
2727/7/2013
28. A few words about the ALOPEX method
• Iterative algorithm.
• Every iteration starts with the data of the previous one.
• In every iteration all the control variables of the cost function can be
changed simultaneously.
• The new values of the variables are stochastically depended from
the change of the cost function between two iterations.
• The stochastic element of the procedure is the noise, which is
controlled from the user.
2827/7/2013
29. Versions of the ALOPEX algorithm
• ALOPEX I
where: , .
• ALOPEX II
where c:constant.
• ALOPEX IIIa
where: .
Also:
2927/7/2013
30. • ALOPEX III
where c(n): interpolation approximation of second degree.
• ALOPEX IVa
where .
• ALOPEX IV
where c:constant.
Also:
3027/7/2013
31. Part 5. Numerical simulations
Applications of ALOPEX algorithm in an Type C aquifer
with 2 and 5 wells, using the MATLAB environment.
3127/7/2013
32. Aquifer type C: A hypothetical test case
2 pumping wells
Aquifer’s parameters:
• L=7000 m
• B=3000 m
• (xw1,yw1)=(1500,700) m
• (xw2,yw2)=(2350,2200) m
• K=100 m/day
• N=30 mm/year
• q=1.23 m2 /day
• d=25 m
• Qtotal=20000 m3/day
• Qlocal_min=(200,200) m3/day
• Qlocal_max=(2500,2500) m3/day
3227/7/2013
Well’s cone of depression:
• radius of influence=300 m
• safety distance=100 m.
34. Penalties definitions
• Qlocal_min penalty∊[1,2]
for i=1:n
if Q(i)(k) ≤ Qlocal_min(i)
Q(i)(k) = Qlocal_min penalty*Q(i)(k)
end
end, at k-th iteration
27/7/2013 34
• Qlocal_max penalty ∊[0,1]
for i=1:n
if Q(i)(k) ≥ Qlocal_max(i)
Q(i)(k) = Qlocal_max penalty*Q(i)(k)
end
end, at k-th iteration
• x-movement penalty ∊[0,1]
for i=1:n
if xT(i)(k) ≥ safety-point(i)
Q(i)(k) = x-movement penalty*Q(i)(k)
end
end, at k-th iteration
• critical-distance penalty ∊[0,1]
for i=1:n
for j=1:n
if front-distance(i,j)(k) ≤ critical-distance(i,j)
Q(j)(k) =critical-distance penalty*Q(j)(k)
end
end
end, at k-th iteration.n: number of wells.
35. Definition of safety points and cone of depression areas
for aquifer wells.
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36. Numerical results using the MATLAB environment
Optimal values for pumping rates:
• Qopt(1)=606.90 m3/day
• Qopt(2)=2598.45 m3/day
ΣQopt(i)=3205.35 m3/day.
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37. 27/7/2013 37
Profit function and pumping rates during a typical
optimization run of 300 iterations.
Penalties activation:
• Qlocal_min penalty: 0 times
• Qlocal_max penalty: 69 times
• x-movement penalty: 139 times
• critical-distance penalty: 42 times.
38. Aquifer type C: Vathi area of Greek island Kalymnos
5 pumping wells
Aquifer’s parameters:
• L=7000 m
• B=3000 m
• (xw1,yw1)=(3932,975) m
• (xw2,yw2)=(2657,1572) m
• (xw3,yw3)=(4873,1586) m
• (xw4,yw4)=(3353,2200) m
• (xw5,yw5)=(4632,2470) m
• K=100 m/day
• N=30 mm/year
• q=1.23 m2 /day
• d=25 m
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Well’s cone of depression:
• radius of influence=300 m
• safety distance=100 m.
• Qtotal=20000 m3/day
• Qlocal_min(i)=200 m3/day
• Qlocal_max(i)=1500 m3/day
41. Profit function and pumping rates during a typical optimization
run of 300 iterations.
27/7/2013 41
Penalties activation:
• Qlocal_min penalty: 3 times
• Qlocal_max penalty: 0 times
• x-movement penalty: 175 times
• critical-distance penalty: 128 times.
42. Aquifer type C: Vathi area of Greek island Kalymnos
Sensitivity analysis
Case a. Optimal values for pumping rates increased by a factor of 2%.
Modified pumping rates:
• Qmod(1)=1.02*875.12 =892.62 m3/day
• Qmod(2)=1.02*237.81 =242.57 m3/day
• Qmod(3)=1.02*847.42 =864.37 m3/day
• Qmod(4)=1.02*596.65 =608.58 m3/day
• Qmod(5)=1.02*1402.19 =1430.23 m3/day
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ΣQmod(i)=4038.37 m3/day.
Aquifer properties, well
properties and penalties
management same as in
original case.
43. Aquifer type C: Vathi area of Greek island Kalymnos
Sensitivity analysis
Case b. Rain factor N increased by a value of 20%.
27/7/2013 43
Optimal values for pumping rates:
• Qopt(1)= 920.08 m3/day
• Qopt(2)= 319.56 m3/day
• Qopt(3)= 1323.68 m3/day
• Qopt(4)= 624.65 m3/day
• Qopt(5)= 1046.31 m3/day
Aquifer properties, well
properties and penalties
management same as in
original case.
Nnew=1.20*30=36 mm/year
ΣQopt(i)= 4234.28 m3/day
(6.95% increase of the sum of
pumping rates from original case)
44. 27/7/2013 44
Aquifer type C: Vathi area of Greek island Kalymnos
Sensitivity analysis
Case c. Ambient water discharge factor q decreased by a value of 20%.
Aquifer properties, well properties
and penalties management same as
in original case.
qnew=0.80*1.23=0.984 m2/day
Optimal values for pumping rates:
• Qopt(1)= 863.12 m3/day
• Qopt(2)= 220.70 m3/day
• Qopt(3)= 714.73 m3/day
• Qopt(4)= 586.88 m3/day
• Qopt(5)= 856.59 m3/day
ΣQopt(i)= 3242.02 m3/day
(18.1% decrease of the sum of
pumping rates from original case)
45. 27/7/2013
Aquifer type C: Vathi area of Greek island Kalymnos
Sensitivity analysis
Case d. Turning off the x-movement penalty.
Aquifer properties and well
properties same as in original
case.
Penalties management:
• Qlocal_min penalty=1.20
• Qlocal_max penalty=0.95
• x-movement penalty=1.00
• critical-distance penalty=0.98
45
• Results: Saltwater intrusion
• Actions: Decrease the critical-distance
penalty to the area of 0.95 (lack of
fine-tuning in the convergence
procedure)
46. 27/7/2013 46
Aquifer type C: Vathi area of Greek island Kalymnos
Sensitivity analysis
Case e. Turning off the critical-distance penalty.
Aquifer properties and well
properties same as in original
case.
Penalties management:
• Qlocal_min penalty=1.20
• Qlocal_max penalty=0.95
• x-movement penalty=0.95
• critical-distance penalty=1.00
• Results: Saltwater intrusion
• Actions: Decrease the x-movement
penalty to the area of 0.70 (lack of
fine-tuning in the convergence
procedure)
47. Discussion and conclusions
• The present work implements the ALOPEX optimization method to
the problem of prevention of salinization in freshwater aquifers.
• The study is based on a well known model of freshwater aquifers
and its analytical solution for the water flow potential. The
ALOPEX method is chosen to calculate the optimal pumping rates
of the aquifer wells, due to the advantages of the method when
compared to other optimization tools.
• Simulations are presented for i) a hypothetical case of an aquifer
with two wells and ii) the real aquifer case of Vathi (on the island
of Kalymnos, Greece). A study on the sensitivity of the optimization
process on the case of the aquifer of Vathi has also been performed,
confirming the efficiency and applicability of the optimization
method, as well as the need of the penalties imposed.
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48. A few words about the advantages of ALOPEX optimization method.
• by incorporating stochasticity, the method effectively finds the global
maxima or minima without local convergence yet in a manner that
does not require inefficient scanning for the solution.
• the profit function of the method is a scalar that measures global
performance and can thus contain a large number of variables (related
to the pumping rates of the aquifer wells), which may be
simultaneously adjusted.
• the same optimization process can be applied in real time and is thus
able to control the volume of pumping water in a real aquifer
environment.
27/7/2013 48
49. 27/7/2013 49
• The method can be applied together with different pumping policies
for the aquifer areas, giving us full control of the pumping
management.
For example, minimum and maximum pumping rates can differ for
every well in controlling the volume of water distributed over the area.
In this way, areas with different water needs (cities or agricultural
areas) can be provided with no-less than the volume of water they
actually need.
• No knowledge of the dynamics of the system or of the functional
dependence of the cost function on the control variables, is required,
making this way the method applicable to further, more realistic
simulations where no analytical solutions are provided.
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