Why We Measure the River Flow in Faisalabad?

1. Where is Faisalabad?

Geographic Background

Faisalabad, in northeast Pakistan's Punjab province, occupies a site in the fertile Indus River plain. It is roughly 180 kilometers southwest of the provincial capital Lahore. Its terrain is generally flat, characteristic of the large alluvial plain formed by the long deposit of sediment carried by the region's rivers over the many millennia. This flat terrain, combined with a semi-arid climate, has shaped the city's landscape and growth patterns. The area experiences hot summers with temperatures often more than 40°C (104°F) and characteristically mild winters, interrupted by spells of cold weather. Annual precipitation is relatively low and the region relies heavily on its river systems for water supply.

Humanistic/Cultural

Faisalabad, or Lyallpur as it was originally known, is a highly culturally and historically endowed city. It was founded in 1892 as a planned colony during the British Raj. The architecture of the city still bears colonial influence, with huge buildings and grid-pattern streets that are very broad. Faisalabad has grown over the years to become a prominent industrial and commercial center of Pakistan, commonly referred to as "the Manchester of Pakistan" because of its thriving textile industry. This industrial development has enticed individuals from all over the country, and the city today is a melting pot of diverse cultures. Local culture is a blend of Punjabi culture, with vibrant festivals, folk music, and traditional cuisine depicting its warm-hearted and welcoming people.

Hydrology and River Overview

The principal river system affecting Faisalabad most is the Chenab River. The Chenab River originates from the higher Himalayas, i.e., the confluence of the Chandra and Bhaga rivers in Lahaul and Spiti valleys of Himachal Pradesh, India. It flows northwest in India's Jammu area and subsequently through Pakistan in the Punjab province. Later, the Chenab River joins with the Jhelum River to form the Panjnad River, which subsequently discharges into the Indus River.

The Chenab River is the most significant river to the Faisalabad area. It supplies water as a necessary source for miscellaneous purposes. Hydrologically, it regulates the water cycle of the surrounding area and influences the groundwater level in the area. Ecologically, the river and its floodplains support a dense array of flora and fauna with habitats for a number of bird, fish, and mammal species. At the level of human activity, the Chenab River is a prime source of agriculture, which constitutes the backbone of the local economy. River water is utilized for irrigation, which enables crops such as wheat, cotton, sugarcane, and rice to be cultivated. The textile industry, which is heavily water consuming, also relies upon the river for water. The river is also used to provide domestic use water, thus meeting the demands of the city's large population on a day-to-day basis.

In Faisalabad's vicinity, the Chenab River has many characteristics. It possesses a wide channel with changing depths, especially under different seasons. There are also a few small tributaries flowing into the river within the region, supplementing the river's flow. The tributaries help in balancing water levels and flow regimes of the main river. The relationship between the river and the city's water system is complex. It supplies water to the city's water treatment plants, which in turn supply industries and homes with clean water. But during periods of high flow, flooding may occur, hence destroying the water supply system and property.

2. How is the River Flow Near Faisalabad?

Factors Influencing it

Rainfall and Runoff

Faisalabad receives a monsoon-dominated climate. The monsoon season typically lasts between July and September and produces much of the annual rainfall. During this period, heavy rains during the upstream catchment areas of the Chenab River result in increased runoff, further swelling the water level and flow rates of the river. In contrast, during the dry season, which encompasses the rest of the year, precipitation is minimal, and river flow is supplemented mainly by Himalayan rainfall-induced snowmelt as well as regulated releases from reservoirs further upriver. Precipitation pattern variability in response to climatic change is becoming more and more extreme, leading to more volatile river flows, and also an increase in both flood and drought likelihood.

Terrain and River Morphology

The flat ground around Faisalabad means that the river has a very gentle slope, which will affect its speed. The width of the Chenab River near the city can range from a few hundred meters to more than a kilometer in certain spots. Depth also differs, with deeper channels in the middle and shallower towards the sides. The river bends and meanders influence the flow patterns as well, creating areas of higher and lower flow. Bed roughness made up of sand, silt, and gravel offers resistance that slows down the water flow speed. The physical characteristics determine the direction of the water flow in the river and may lead to sedimentation and erosion in different parts of the river channel.

Reservoir Operations

There are several reservoirs and dams higher up on Faisalabad's side of the Chenab River, such as the Marala Headworks and the Rasul Barrage. These reservoirs hold water for irrigation, power generation, and water storage. The operation of these reservoirs, e.g., water release, has significant impacts on the flow of the downstream river. During the dry season, reservoir releases in a controlled way ensure a minimum guaranteed flow in the river, keeping the water bodies ecologically balanced and ensuring water supply for agriculture and domestic uses. However, during heavy rains or when the reservoirs become full, a largescale release is likely to occur, which may lead to sudden rise of river flow and high probability of flooding downstream.

Historical Hydrological Events

While specific historical flood and drought events in Faisalabad with detailed and reliable sources are difficult to find together, Pakistan as a whole has experienced serious hydrological events in the past. For example, Pakistan experienced extensive floods in recent decades, such as the 2010 floods, which affected a large part of the country, including the Punjab region. Though specific information about the impacts of such floods on Faisalabad itself may be scarce, it can reasonably be believed that the city, as it is located on the Chenab River, would have been impacted to some extent. These floods would have caused general flooding, obliteration of fertile lands, and disruption of water supply and transportation networks. Similarly, there have been droughts too in the region, which cause water shortage for agriculture and household use, and impact the local economy and life of the people. These events must be monitored because this would allow one to comprehend the natural variability of river flow, predict future events, and design effective flood - control and water - management plans to safeguard the city and its population.

3. How to Measure the River Flow in Faisalabad?

Traditional Methods

Surface Drift Buoy Method

Surface drift buoy method is one of the simplest methods to measure river flow. In this method, free floating bodies such as buoys and others are released on the surface of the river. The movement or drift of these buoys is then measured over a known distance and time interval. By measuring how long it takes for the buoy to travel a specific distance, the river's surface speed can be calculated. Although easy to perform and needing minimal equipment, this method is severely flawed. It only provides a reading of the movement on the surface of the river, and not of the flow pattern in the deeper sections. Apart from this, the movement of the buoy can be induced by wind, leading to erroneous velocity readings.

Anchored Boat Method (Manning's Table/Current Meter)

Anchored boat method involves the deployment of an anchored boat in a specific point along the river. A current meter, which is a device for the measurement of the water velocity, is subsequently dropped into the river in different depths and locations. By taking a number of measurements of velocity at various points across the river cross-section, a full profile of the river flow at the specified location can be established. This method provides more accurate information than the surface drift buoy method because it measures the flow at various depths. It is, however, time - consuming, labor - intensive, and poses risks to safety for the involved personnel, particularly in turbulent or fast - flowing water.

Introduction to ADCP: Acoustic Doppler Current Profiler

ADCP is a more efficient and sophisticated technology used for river flow measurement. Unlike traditional methods, ADCP can provide continuous profiles of river flow over its entire depth and width within a relatively short time. ADCP is an non-invasive technique, which implies that it does not entail actual contact with water or the installation of permanent infrastructure within the river. This makes it safer both for the operators and the aquatic ecosystem. ADCP can quickly acquire high rates of data, which can be used in a variety of applications, including flood forecasting, water resources management, as well as ecologic studies.

4. What Does ADCP Based on the Doppler Principle Do?

The ADCP operates based on the Doppler principle. It emits acoustic pulses into the water column. The acoustic pulses bounce back from microscopic particles suspended within the water, like plankton or sediment. If the water is moving, the backscattered signal frequency changes in proportion to the speed of the water. By monitoring this change in frequency (the Doppler shift), the ADCP can calculate the speed of the water at different points and depths within the water column. The device is equipped with a number of transducers that transmit and receive the acoustic signals, thereby allowing it to build a three-dimensional profile of the river flow. The data is then calculated to derive in-depth data about the characteristics of the river flow such as velocity, direction, and volume.

5. What is Required for High-Quality River Flow Measurement in Faisalabad?

Equipment Requirements

Material Dependability

For precise measurements of river flow at Faisalabad, ADCP equipment needs to be built using trustworthy materials. Since ADCP is typically installed in the river, it has to go through various environmental conditions, such as water corrosion, sediment abrasion, and changes in temperature. High-grade stainless steel and tough plastics are extensively used so that the device will be stable and strong. Also, some ADCPs are made of titanium alloys, which are highly resistant to corrosion and extremely robust and can be employed long-term in the harsh river environment.

Small Size and Light Weight

Compactness and light weight are important characteristics of ADCP equipment. This allows for hand portability of the device, mounting, and manual handling, especially where there is restricted access to the river. A compact ADCP can be mounted on small boats quite easily or mounted on stationary structures within the river. It also has minimal impact on the stability of the boat during measurement taking and minimum labor in hand handling.

Cost - Effectiveness

Cost - effectiveness is an important factor in choosing ADCP equipment to monitor river flow in Faisalabad. The equipment should be able to produce accurate and reliable data at an affordable price. This is especially applicable to local government bodies, research centers, and small - scale water management projects that have budget limitations. Cost - effective ADCPs will render river flow monitoring affordable and viable in the long run.

6. How to Choose the Right Current Measurement Gear?

Implementation Tactics

Boat - Mounted (Moving Boat) ADCP

The boat - mounted ADCPs are appropriate for surveying vast tracts of rivers, river discharges, and quick plotting of river flow patterns. They are highly mobile and can survey extensive portions of the river within very short duration. This is the kind of ADCP that can be used in situations where a broad awareness of the flow characteristics of the river across a wide area needs to be established, including in flood-control investigations or large-scale water resource planning projects.

Bottom - Mounted (Fixed) ADCP

Bottom-mounted ADCPs are employed for long, continuous base flow monitoring of river flow. They are mounted on the river bed and are capable of collecting data over extended durations without continuous human intervention. They are suitable for base flow monitoring, trends in river flow over the long term, and for ecological studies involving continuous data acquisition.

Cableway ADCP

Where there is an existing cableway infrastructure along river reaches, cableway ADCPs provide a handy option. Cableway ADCPs are suspended from the cableway and can be transported across the river to take measurements at different locations. This can be of benefit in making accurate measurements of the flow in wide rivers where boat-based measurements become inconvenient or hazardous.

Working Frequency

The choice of working frequency in an ADCP is significant as it will affect the range and resolution of the measurements. A 600 kHz ADCP will typically be able to measure up to a horizontal distance of 70 meters and is therefore suitable for medium-sized rivers or to obtain detailed measurement in small areas. It gives relatively high-resolution data that is well suited to examine complex flow patterns. Conversely, a 300 kHz ADCP would have a greater range of up to 110 meters and would be more suited for big rivers or where there is a need for greater coverage of the river cross-section. It could, however, be less resolved than the 600 kHz ADCP.

Brand Recommendations

Globally, well-known brands of ADCPs include Teledyne RDI, Nortek, and SonTek. These brands are well-known for their quality products, state-of-the-art technology, and consistent performance. However, if one desires a low - cost option, the ADCP manufacturer Chinese brand "China Sonar Panda ADCP" is an ideal choice. This "economy ADCP" is made of all - titanium alloy material, which is extremely robust and corrosion - proof. It is extremely cost-saving, hence applicable for a wide range of uses, from small-scale research work to neighborhood water management projects. For more information, you can visit their site at https://china-sonar.com/.

Here is a table with some well known ADCP instrument brands and models.