The Purpose of project task

1. Mengenal pasti penyata masalah yang melibatkan sumber bekalan air yang berlaku terhadap sesuatu masyarakat. 2. Mengenal pasti kaedah pembinaan yang melibatkan penyaluran air bawah tanah sebagai alternatif dalam mengatasi masalah sumber bekalan air yang berlaku terhadap masyarakat tempatan3. Membandingkan sistem pembinaan melibatkan air bawah tanah yang dijalankan di Malaysia dengan sistem yang dijalankan di luar negara4. Membincangkan maslahah yang diperolehi daripada alternatif pembinaan melibatkan penyaluran air bawah tanah semasa dan masa hadapan

Material

i. Bahan-bahan rujukan yang diperolehi sama ada secara langsung mahupun tidak langsung

The Purpose of project task

1. To Identify statements that involve problems occurring sources of water supply to local communities

2. To Identify the method of construction, which involves the supply of groundwater as an alternative to solve the problem of water supply which applies to local communities

3. Comparing the construction system involving groundwater conducted in Malaysia with a system that performed overseas

4. To Discuss the uses obtained from alternative involves construction of an underground water supply the current and future

Material

Reference materials were obtained either directly or indirectly

Chapter 1 : Shallow Tube Well

1) Water Scarcity Problem in Dry Season for the Irrigation of Paddy Field

In most of Asia, rice is not only the staple food, but also constitutes the major economic activity and a key source of employment and income for the rural population. Water is the single most important component for sustainable rice production, especially in the traditional rice growing areas of the region. Reduced investments in irrigation infrastructure, increased competition for water and large water withdrawals from underground water lower the sustainability of rice production. However, despite the constraints of water scarcity, rice production must rise dramatically over the next generation to meet the food needs of Asias poor. Producing more rice with less water is therefore a formidable challenge for the food, economic, social and water security of the region.

The past years have seen a growing scarcity of water worldwide. The pressure to reduce water use in irrigated agriculture is mounting, especially in Asia, where it accounts for 90% of total diverted fresh water. Rice is an obvious target for water conservation: it is grown on more than 30% of irrigated land and accounts for 50% of irrigation water.

Figure 1: Beautiful paddy field view in Malaysia

Most of the approximately 22 million ha dry season irrigated rice areas in south and South-East Asia fall in the economic water scarcity zone. However, there may be an overestimation of the water availability in the dry season because IWMIs water-scarcity calculations are based on the annual water balance.

In principle, water is always scarce in the dry season, when the lack of rainfall makes cropping impossible without irrigation. Rice production in Asia needs to increase to feed a growing population. Though a complete assessment of the level of water scarcity in Asian rice production is still lacking, there are signs that declining quality of water and declining availability of water resources are threatening the sustainability of the irrigated rice-based production system. Drought is one of the main constraints for high yield in rain-fed rice.

2) Application of Shallow Tube Well for Irrigation of Paddy Crops Especially in Dry Season Groundwater irrigation is one of the alternative methods to irrigate the paddy crops beside surface water. The use of shallow tube well for paddy irrigation is able to overcome water scarcity especially during dry season and off planting season in Malaysia. The performance of a shallow tube well was evaluated based on well efficiency and pump efficiency. In Malaysia, IADA Seberang Perak area was chosen as a pilot project for groundwater irrigation due to potentially available fresh water on it shallow aquifer and low water table at this area where indirectly it can reduce the pumping cost. Groundwater was used to irrigate the paddy field on August-December in 2009.

Figure 2: Illustration of Shallow Tube Well Theoretically, in shallow well technology, hand pumps are operated in a suction mode. A suction pump draws water from shallow depth by creating a vacuum in the suction pipe. The suction hand pump can practically extract water from a depth of 7.5 m from ground level.

a) Material and Method

The test plot was supplied by groundwater extracted from shallow tube well during pre-saturation and normal growth. Fertilizer and insecticide were applied to the area as normally applied to the other plot by the farmer. Irrigated water was controlled by on-off automatic water level controller and control panel. Water distributions and monitoring system consist of one unit of submersible pump, two units of water level transducers, one unit of control panel and two units of flow rate meter. The water was distributed by using polyethylene pipe. The schematic diagram of water distribution system is shown in Figure 3. The volume of rainfall was recorded by weather station which located near to the site.

Figure 3: Schematic Diagram of Water Distribution System at Seberang Perak

b) Well Performance

The performance of the pumping well was evaluated by conducting step drawdown pumping test. The water was pumped at different discharge rate and at the same time, the water level inside the well was observed. The test was designed in three steps. The time for each step was set for 2 h. After 2 h, the rate of pumping was increased to the next steps continuously without stopping the pump. The single-three phase inverter was connected to the centrifugal pump to vary the discharge rate. The discharge rate was measured by flow rate meter. Centrifugal pump (Leo) two-horse power was used to pump the water from pumping well and water level was measured by water level transducer (levelogger Solint).

c) Pumping Performance

The 1.16 kW submersible pump (Grundfos) was installed about 1 m from the top of the pumping wells screen. The depth of pumping well is 11 m from ground surface. The system was provided with flow rate meter to measure the volume of water abstracted from the shallow tube well. The ball valve was installed before flow rate meter to prevent water backflow when the pump is shut off. The water level inside the well was monitored by water level transducer (levelogger Solint) where it records the water level hourly and it is located 1 m below submersible pump location.

d) Well Efficiency

In each step, aquifer loss is always greater than well loss and this indicate that the major influence of drawdown inside the pumping well is controlled by aquifer loss component.The well efficiency decrease when discharge rate is increased .When more water is pumped, the well efficiency decreases due to obstruction near the well screen. The tube well efficiency decrease when the discharge of water increase in step pumping test on a tube well. The difference in well efficiency might be due to the tested well is the new constructed tube well.

The values of specific capacity of the well indicated that the developed well was classified as moderately productive well. The high value of specific capacity is better because it shows the better and highly productive well. Low value of specific capacity implies low production of well and the screen of the well might be cloggy. There are two assumptions in estimating specific capacity of the well. First, the well is pumped at the constant rate until it achieves steady state condition. Second, the drawdown within the tested well is a combination of the decrease in hydraulic head within the aquifer and head loss due to turbulent flow within the well.

e) Pumping Efficiency

The actual flow rate of submersible pump was obtained from the pumping activity. The discharge values were arranged and the actual discharge was taken. The theoretical flow rate was obtained from submersible pump performance curve produced by manufacturer based on the total dynamic head. The suction head of submersible pump is zero indicates that the suction region of the pump is already submerged into water. Pump efficiency is very important to be considered because it shows the performance and the reliability of the pump during irrigation process. The submersible pump is suitable to be used due to it high efficiency. The pumps motor which already submerged into the water makes the water as natural cooler for the pump. Submersible pump is an economic pump due to it high efficiency and good operating condition.

f) Water Demand and Water Supply.

The supplying of groundwater to the paddy plot is controlled by the control panel. The water level sensor is located at the paddy plot where it gives the signal to the control panel to switch-on or switch-off the pump. The farmer can adjust the standing water level at the planting plot by adjusting the scale or depth of water at the water level sensor. If the groundwater amount is achieving the required standing water level at the plotting area, the control panel will switch-off the submersible pump automatically. However, if there are rainy days, the irrigation process to the paddy plot is indirectly assisted by the rainwater. Indirectly, the amount of groundwater abstracted and pumping cost can be reduced. If there is excess water at the paddy plot, the water will flow to the overflow pipe which already installed at the early time of planting.

Chapter 2 : Horizontal Collector Well

Kelantan is located in the north-eastern part of Peninsular Malaysia. The Kelantan River (also known as Sungai Kelantan in the Malay language) is the largest river in the Kelantan State. It is fed by more than 180 streams and drains a catchment area of approximately 11900 km2. The Kelantan River is considered to be a middle lowland stream flowing toward the river mouth. Annual rainfall in the Kelantan River area ranges from 01750 mm throughout the year. The river flows northward, passing through important towns such as Kuala Krai, Tanah Merah, Pasir Mas and Kota Bharu, the state capital, before discharging into the South China Sea.

The Kelantan River is formed from the combination of the Galas River (Sungai Galas) and the Lebir River (Sungai Lebir) near Kuala Krai. The Kelantan River has been used heavily by the local people for domestic uses, transportation, agriculture, plantation irrigation, small scale fishing industries and also sand mining activities. The Kelantan Rivers water has been turbid since the early 1990s because of the high amount of suspended solids and siltation. These were caused by logging activities in the upstream areas (Lojing Highlands) and sand mining activities. There are approximately 128 sand mining operations along the Kelantan River from Kuala Krai to Tumpat. The volume of sand mining activity along the Kelantan River increases each year because of the high demand of sand for industry and construction.

Figure 4 : Kelantan RiverThere are two types of sources that sand is mined from, terrestrial and marine deposits. The most common terrestrial sources are river channel deposits, floodplain alluvial deposits and residual soil deposits; the marine sources are the shore and offshore deposits. In Malaysia, the main source of sand is from in-stream mining. This type of mining is a common practice because mining locations are usually near the market or along a transportation route, which can reduce transportation costs. Sand mining is an activity within a state's capability and is supported by the federal government. The sand mining permits are provided by the Department of Irrigation and Drainage (DID), whereas the approval of the permits is decided by the District and Land Office (Kelantan). To date, there is no illegal set up of sand mining along the Kelantan River, except for few companies that are operating with expired sand mining permits.

Overall, the Kelantan government still manages to control the number of sand mining operations along the Kelantan River. The Department of Mines, under the Ministry of Primary Industry, is the main federal agency that administers the provisions on environmental protection measures prescribed in the Mining Enactment. However, the enforcement by the Department of Irrigation and Drainage of the river sand mining guidelines and monitoring still must be strengthened. In recent years, the sand mining activities in Malaysian rivers have created several environmental problems, such as the deterioration of river water quality, bank erosion, river bed degradation and buffer zone encroachment. All of these are results of excessive sand extraction along the river. Heavy rainfall and soil erosion have resulted in severe sedimentation of Malaysian rivers. Rapid developments, such as land clearing for urban housing, logging and agriculture, have caused erosion and sedimentation in the rivers.

How to enhance the safe of water supply source besides the river? Another source of clean water besides rivers is groundwater. So, one of the method to reach groundwater is by using Horizontal Collector Well.