Water resources assessment would include the definition of river basin as a geographycal unit for assessing water resoures; the hydrological analysis to assess the availability of surface and groundwater within a river basin, as well as the flood characteristics during the wet season; water demand analysis for assessing the water supply requirement; and the elements of river basin development for sustaining the human welfares.
1.1 River basin definition:
River Basin is a geographical area determined by the watershed limits of the system of waters, including surface and underground waters, flowing into a common terminus (See Figure 1.1).
1.2.1 Selection of Hydrological Stations.
Figure 1.2 below is an example of a map that shows the location of rainfall stations and river gauging stations at the Baram river basin, Sarawak.
From the inventory of hydrological stations, the location, the length of records (daily or manual, and continuous or automatic), and the quality data are the things that should be considered in selecting rainfall stations and the river gauging stations for the planning purposes.
1.2.2 Rainfall Analysis
Depend on the purposes of a study; rainfall analysis for water availability can be done for weekly, monthly or annually. While for extreme conditions (flood), short duration data (less than 24 hours) are used for the analysis.
The points data from rainfall stations are usually need to be regionalized by using the appropriate method, such as:
1.2.3 Estimating Runoff
The formula for estimating runoff is:
R = P – L – G,
Where:
R = runoff (mm)
P = precipitation or rainfall (mm)
L = Basin recharge (mm), which is the portion of precipitation that does not contribute to stream flow or groundwater. It consists of evaporation, interception, depression storage, soil moisture.
G = Groundwater accretion or accumulation (mm)
In estimating the annual runoff, and for an approximation, G can be eliminated and L can be considered as evaporation only.
1.2.4 River Flow Analysis
The river gauging stations can be a staff gauge, where the water level are recorded manually (two or three times a day), or an automatic water level recorder that record the water level data continuously.
Beside water level measurements, the discharge, sediment load, and water quality are also measured to develop:
1.2.5. Groundwater Yield:
The subsurface water conditions can be categories as:
Vx = Kx * dH/dx
Where: Vx = velocity in the x direction
Kx = Coefficient of permeability; and
dH/dx = hydraulics gradient
Depend on its geological condition; an aquifer is defined as a formation or geological materials that can keep and release water in an adequate amount. The aquifer has a good potential if it can release more than 200 gpm; it is a fair potential if can only release water between 50 and 200 gpm; and it is poor potential, if can release water less than 50 gpm.
Furthermore there are two types of aquifers; confined and unconfined aquifer.
Groundwater yield is determined by conducting groundwater pumping test using two observation wells, or one observation well, or without observation well.
1.3 Water Demand
1.3.1 Domestic consumption
Domestic consumption that has been used for forecasting the demand in the Master Plan for Kuching Water Board is as shown in Table 1.3.1:
Table 1.3.1 Domestic consumption
Domestic consumption ___________ (l/capita/day)
Year ____________--1998 --2000 --2005 --2010-- 2015 --2020
Urban ___________---240 ---245 ---260 ----275 ----290 --300
Standpipes ________----50 ----50 -----50 -----50 -----50 ---50
Rural ____________---140 ---155 ----170 ----180 ----190 -200
1.3.2 Commercial/Institutional consumption
For commercial/institutional consumption the water demand forecast is base on these assumptions:
Table 1.3.2 Commercial/institutional Consumption
Commercial consumption __________ (l/capita/day)
Year _____________1998 --2000 --2005 --2010 --2015 --2020
_________________ 107 ---109 ----112 ----115 ---118 ----121
1.3.3 Industrial Consumption
Assumptions that have been used in water demand forecasting for industrial water consumption are as follows:
Table 1.3.3 Industrial Consumption
Type of Industry _____________Consumption
Cotton ____________________400 l/employee/day
Beer with cooling process_______ 17 – 23 l/ l beer
Beer without cooling process ______5 – 7 l/ l beer
Milk processing _______________3 – 6 l/ l milk
Wool processing ______________1000 l/ kg wool
Sugar cane processing __________100 l/ kg sugar
Paper production (soft paper) _____1500 – 3000 l/ kg
Paper production (printing) ______400 – 600 l/ kg
The actual use will be influence by the price and availability of water, the degree of recycling/multiple use of water, and efficiency.
1.3.4 Non Revenue Water (NRW)
Non Revenue Water is losses that occur through leakages, releases for fire fighting, or the flushing of main distribution system.
1.3.5 Total Urban or Rural Water Supply.
Total urban or rural water supply is:
The total water consumptions + Non revenue water.
1.3.6 Agricultural Water Demand
1.3.7. Aquaculture Water Demand
1.4 Elements of Water Resources Development
The elements of water resources development plan are shown in Table 1.4 below:
1.1 River basin definition:
River Basin is a geographical area determined by the watershed limits of the system of waters, including surface and underground waters, flowing into a common terminus (See Figure 1.1).
Figure 1.1 River Basin
1.2 Hydrological Analysis for water availability, and extreme conditions
1.2.1 Selection of Hydrological Stations.
Figure 1.2 below is an example of a map that shows the location of rainfall stations and river gauging stations at the Baram river basin, Sarawak.
Figure 1.2 Hydrological Stations at Baram River Basin
From the inventory of hydrological stations, the location, the length of records (daily or manual, and continuous or automatic), and the quality data are the things that should be considered in selecting rainfall stations and the river gauging stations for the planning purposes.
1.2.2 Rainfall Analysis
Depend on the purposes of a study; rainfall analysis for water availability can be done for weekly, monthly or annually. While for extreme conditions (flood), short duration data (less than 24 hours) are used for the analysis.
The points data from rainfall stations are usually need to be regionalized by using the appropriate method, such as:
- Thiessen Polygon
- Isohyets
- Arithmetic mean
1.2.3 Estimating Runoff
The formula for estimating runoff is:
R = P – L – G,
Where:
R = runoff (mm)
P = precipitation or rainfall (mm)
L = Basin recharge (mm), which is the portion of precipitation that does not contribute to stream flow or groundwater. It consists of evaporation, interception, depression storage, soil moisture.
G = Groundwater accretion or accumulation (mm)
In estimating the annual runoff, and for an approximation, G can be eliminated and L can be considered as evaporation only.
1.2.4 River Flow Analysis
The river gauging stations can be a staff gauge, where the water level are recorded manually (two or three times a day), or an automatic water level recorder that record the water level data continuously.
Beside water level measurements, the discharge, sediment load, and water quality are also measured to develop:
- Discharge Rating Curve;
- Sediment Rating Curve; and
- Water Quality concentration.
1.2.5. Groundwater Yield:
The subsurface water conditions can be categories as:
- Saturated groundwater;
- Capillary water; and
- Soil moisture.
Vx = Kx * dH/dx
Where: Vx = velocity in the x direction
Kx = Coefficient of permeability; and
dH/dx = hydraulics gradient
Depend on its geological condition; an aquifer is defined as a formation or geological materials that can keep and release water in an adequate amount. The aquifer has a good potential if it can release more than 200 gpm; it is a fair potential if can only release water between 50 and 200 gpm; and it is poor potential, if can release water less than 50 gpm.
Furthermore there are two types of aquifers; confined and unconfined aquifer.
Groundwater yield is determined by conducting groundwater pumping test using two observation wells, or one observation well, or without observation well.
1.3 Water Demand
1.3.1 Domestic consumption
Domestic consumption that has been used for forecasting the demand in the Master Plan for Kuching Water Board is as shown in Table 1.3.1:
Table 1.3.1 Domestic consumption
Domestic consumption ___________ (l/capita/day)
Year ____________--1998 --2000 --2005 --2010-- 2015 --2020
Urban ___________---240 ---245 ---260 ----275 ----290 --300
Standpipes ________----50 ----50 -----50 -----50 -----50 ---50
Rural ____________---140 ---155 ----170 ----180 ----190 -200
1.3.2 Commercial/Institutional consumption
For commercial/institutional consumption the water demand forecast is base on these assumptions:
Table 1.3.2 Commercial/institutional Consumption
Commercial consumption __________ (l/capita/day)
Year _____________1998 --2000 --2005 --2010 --2015 --2020
_________________ 107 ---109 ----112 ----115 ---118 ----121
1.3.3 Industrial Consumption
Assumptions that have been used in water demand forecasting for industrial water consumption are as follows:
Table 1.3.3 Industrial Consumption
Type of Industry _____________Consumption
Cotton ____________________400 l/employee/day
Beer with cooling process_______ 17 – 23 l/ l beer
Beer without cooling process ______5 – 7 l/ l beer
Milk processing _______________3 – 6 l/ l milk
Wool processing ______________1000 l/ kg wool
Sugar cane processing __________100 l/ kg sugar
Paper production (soft paper) _____1500 – 3000 l/ kg
Paper production (printing) ______400 – 600 l/ kg
The actual use will be influence by the price and availability of water, the degree of recycling/multiple use of water, and efficiency.
1.3.4 Non Revenue Water (NRW)
Non Revenue Water is losses that occur through leakages, releases for fire fighting, or the flushing of main distribution system.
1.3.5 Total Urban or Rural Water Supply.
Total urban or rural water supply is:
The total water consumptions + Non revenue water.
1.3.6 Agricultural Water Demand
1.3.7. Aquaculture Water Demand
1.4 Elements of Water Resources Development
The elements of water resources development plan are shown in Table 1.4 below:
Table 1.4 Elements of Water Resources Development Plan
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