Groundwater Resources Groundwater Resources
Management/Salinity Intrusion Management/Salinity Intrusion
Modelling Modelling
M. M. Elfleet Elfleet
Introduction Introduction
This work includes the development and application of two models specially written to describe the conditions of the coastal aquifer:
1. A 1Layer 2dimensional model was used to provide some initial understanding of the aquifer under
extreme abstraction regimes encountered, and
2. A 2 layered 2dimensional groundwater model to better understanding the behaviour of the groundwater
interface.
The study considers the long-term implications for a coastal aquifer recovery following the implementation of different management strategies in the region.
Salinity/freshwater interface in the aquifer for different abstraction profiles are considered.
Importance of water resource management
Most of the world’s public water supply comes from aquifers e.g. Libya 97
Coastal areas - groundwater resource and saltwater intrusion
Tripoli case - over the past 30 years demand
has exceeded recharge by a factor of 8.
Tripoli Geological Map
Tripoli Geological Map
Water Balance for Modelled Area Water Balance for Modelled Area
Year Total demand (Mm
3/yr)
Total Abstracted from Upper aquifer
(Mm3/yr)
Total Recharge (returned plus)rainfall
(Mm3/yr)
net loss from upper aquifer
(Mm3/y)
1930 6 6 11.4 -5.4
1960 25 15 14.5 0.5
1980 140 94 33.8 60.2
1990 150 94 35.5 58.5
2000 155 21.9 36.3 -14.4
2010 180 31.4 40.5 -9.1
Aquifer water elevation Aquifer water elevation
100 105 110 115 120 125 130 135 140 145 150
1920 1940 1960 1980 2000 2020 2040 2060
Year
Head drawdown(m)
Scenario1 Scenario2 Scenario3
Velocity vectors 1990
Velocity vectors 1990
2L 2L - - 2D Simulation at the year 1990 (Scenario 3) 2D Simulation at the year 1990 (Scenario 3)
Year 1990
350 400 450 500 550
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Distance from coast (km)
Elevation (m)
Top height Freshwater Saline Base_Line
2L 2L - - 2D Simulation at the year 2160 (Scenario 3) 2D Simulation at the year 2160 (Scenario 3)
Year 2160
350 400 450 500 550
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Distance from coast (km)
Elevation (m)
Top height Freshwater Saline
Base_Line
