Why We Monitor the River Flow at Peshawar？

1. Where is Peshawar?

Geographic Background

Peshawar, the provincial capital of Khyber Pakhtunkhwa province of Pakistan, is found in the northwestern part of the country. It lies at the eastern end of the Khyber Pass, an old commercial route that has been linking South Asia and Central Asia since centuries. Surrounded by the Spin Ghar Mountains in the north and the west, and bordering the Indus River plains in the east, the altitude of Peshawar ranges from approximately 300 to 400 meters above sea level.

The city's climate is semi-arid with distinct seasons. The summers are extremely hot, with temperatures frequently exceeding 40°C (104°F), whereas the winters are cold, with temperatures dropping to around 5°C (41°F) during the cold season. Annual rainfall is uncommon, and its mean is around 120 - 200 millimeters and confined to July to September monsoon. Its arid weather, capped by its hilly terrain, forces the river systems inside and outside of Peshawar to assume a vital role in sustaining life, agriculture, and economic functions.

Humanistic/Cultural

Peshawar is the second-oldest city in South Asia, and it boasts a long and multicultural past of over 2,000 years. It has been ruled by many civilizations, such as the Achaemenid Empire, the Mauryan Empire, the Kushans, the Mughals, and the British, each of whom left their imprint on the city's buildings, customs, and way of life.

The city's architecture is a testament to its past. Landmarks such as the Qissa Khwani Bazaar, or "Storytellers' Bazaar," have been commercially successful and a focal point of social activity for centuries. The narrow streets of the bazaar are lined with shops selling traditional handicrafts, spices, and fabrics. The Peshawar Museum contains a vast collection of Gandhara civilization artifacts and symbolizes the city's Buddhist heritage, featuring intricate sculptures and items from the 1st - 5th centuries CE.

Culturally, Peshawar is predominantly Pashtun in nature. Music and instruments like rubab and dholak are part of celebrations and festivals. Classical dances like the Attan are performed with plenty of energy, depicting the rich nature of the Pashtuns. Cuisine is a mix of food flavors, with chapli kebabs, karahi, and pulao being some of the most coveted dishes, attracting gourmands from far and wide.

Hydrology and Overview of River

The Kabul River is the primary watercourse that significantly affects Peshawar. The Kabul River arises in the Sanglakh Range of the Hindu Kush mountains within Afghanistan and flows east through the Khyber Pass to Pakistan, eventually draining into the Indus River. The Kabul River has been a focal figure in Peshawar historically.

The Kabul River has historically been a significant route of communication that served to connect South Asia and Central Asia through people, as well as goods, exchange. It continues to be a lifeline to the city with domestic consumption, irrigation, and industrial utilization. The river's waters flow via a network of canals to irrigate large agricultural tracts around Peshawar and sustain the cultivation of crops such as wheat, maize, sugarcane, and fruits.

The Kabul River and its wetlands maintain a wide distribution of flora and fauna. However, the river also faces several problems. Industrial waste, home sewage, and agriculture runoff contribute to poor-quality water, posing a threat to human and ecosystem health. Heavy runoff in the upper reaches of the river causes a flood during monsoon time, which will put people's lives at risk and threaten infrastructure.

2. What is the River Flow Near Peshawar?

Affecting Factors

Rainfall and Runoff

Rainfall is the predominant factor influencing the river flow near Peshawar. Excessive rains in the upcountry catchment areas of the Kabul River, particularly in the Afghan mountains, during the monsoon season lead to a significant increase in runoff. The additional water flows downstream, and the river's water level and flow rate increase significantly. In contrast, during the dry season, with low rainfall, river flow is dominated by mountain snowmelt and releases from regulated upstream dams and reservoirs. Climate change has also disrupted these traditional patterns, with more fluctuating rainfall, premature snowmelt, and more frequent extreme events, making it more difficult to predict river flow.

Terrain and River Morphology

The mountainous surrounding of Peshawar, the steep mountain slopes, and little valleys play a decisive role in the flow of the Kabul River. The river runs swiftly through the mountains as it passes through them and cuts out deep gorges and transports gigantic loads of sediment. When the river enters the plains surrounding Peshawar, the slope declines, and the water slows down and settles, altering the curvature and depth of the plains with the passage of time. The presence of boulders and rock outcrops in the mountainous sections also provides areas of turbulence and varying flow rates, which add complexity to the hydrologic characteristics of the river.

Reservoir Operations

There are several dams and barrages built upstream of Peshawar on the Kabul River and its tributaries for water storage, irrigation, power generation, and flood control. For example, the Darunta Dam in Afghanistan regulates the river flow to some extent. Regulated releases from the dams during the dry season ensure a minimum guaranteed flow of water in the river, creating ecological harmony and meeting the water needs of Peshawar and the neighboring areas. However, large-scale releases during intense precipitation or when the reservoirs are full can occur in which may influence sudden river surges of flow and increase the likelihood of downstream flooding in the Peshawar region.

Historical Hydrological Events

Peshawar has witnessed several major floods due to the unstable nature of the Kabul River. The most devastating flood in recent memory occurred in 2010. Unusual early snow melt and heavy monsoon rain led to widespread flooding throughout the region. The Kabul River overflowed its banks, inundating large sections of Peshawar and crops in the surrounding area. Thousands of homes were wrecked, and hundreds of thousands left homeless. The flood also inflicted heavy damage to infrastructure like roads, bridges, and irrigation channels, and brought massive economic losses. Monitoring such past hydrological events is necessary for deciding the river's behavior during extreme conditions as well as in planning for efficient flood - control policy and disaster - response measures.

3. How to Observe the River Flow in Peshawar?

Traditional Methods

Surface Drift Buoy Method

Surface drift buoy method is a straightforward technique of measuring river flow. There are floating bodies, such as plastic or wooden buoys, released on the surface of the river. By measuring the distance traveled and the time taken by the buoys, the velocity of the river on the surface can be estimated. There are some limitations to this method. It is only a measure of the surface flow and can be affected by wind, providing false readings, especially in the turbulent water of the Kabul River north of Peshawar.

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

Anchored boat method is to moor a boat at a specific place in the river and measure the velocity of water at different depths and places using a current meter. A number of measurements are taken along the cross - section of the river to generate an overall profile of the river flow. Though this method generates more accurate data than does the surface drift buoy method, it is labor-intensive and time - consuming and is also associated with safety risks, especially in the high - speed and usually unstable waters of the Kabul River.

• *Introduction to ADCP: Acoustic Doppler Current Profiler

Acoustic Doppler Current Profiler (ADCP) gives a more advanced and efficient way of measuring river flow. It has the capacity to give continuous profiles of the river flow throughout its whole depth and width in a relatively shorter time. As a non-contact technique, ADCP does not entail direct water contact or the installation of permanent structures within the river and is consequently safer for operators and aquatic life. In the rugged environment of the river surrounding Peshawar, ADCP's ability to quickly collect massive data quantities is pure gold when it comes to flood forecasting, water resources management, and ecological studies.

4. What Is ADCP Based on the Doppler Principle?

The ADCP operates based on the Doppler principle. It emits acoustic pulses into the water column, which bounce off suspended small particles in water, e.g., sediment or plankton. When the water is in motion, the frequency of the backscattered signals changes according to the velocity of the water. By detecting the change in frequency (the Doppler shift), the ADCP can calculate the velocity of the water at different depths and locations in the water column. A number of transducers on the device transmit and receive the sound waves, enabling it to create a three-dimensional picture of the river flow, providing precise information of the river's pattern of flow.

5. What is Required for High-Quality Measurement of Peshawar River Flow?

Equipment Requirements

Material Reliability

To achieve accurate river flow measurement in Peshawar, ADCP gear should be constructed of strong materials. The Kabul River water can be turbulent during floods and have abrasive sediment, while pollution also corrodes equipment. High-grade stainless steel, titanium alloys, and abrasion-resistant engineering plastics are the preferred materials because they are corrosion-resistant, abrasion-resistant, and impact-resistant, ensuring the longevity and stability of the ADCP device in the harsh river environment.

Compact Size and Light Weight

Because of the hilly, and in many places inaccessible, terrain that surrounds Peshawar, a compact, light-weight ADCP is strongly desirable. It allows easy carriage to remote locations of measurement on foot, in a vehicle, or small boat. A compact unit reduces the labor of handling and deployment, enabling more efficient gathering of data within the variable river systems of the region.

Cost - Effectiveness

Cost effectiveness is the key issue when choosing ADCP equipment to be used in Peshawar. The research centers, water management departments, and local government departments have limited funds. An ADCP that offers good quality data at a low cost is essential to facilitate regular and sustainable river flow monitoring, which is crucial for effective management of water resources in the city.

6. How to Choose the Correct Current Measurement Hardware?

Deployment Methods

Boat - Mounted (Traveling Boat) ADCP

Boat-mounted ADCPs may be employed in surveying larger sections of the Kabul River near Peshawar where the river can be reached by boat. They can cover long distances at a quick speed and therefore are the ideal ones for creating maps of river flow regimes, monitoring river discharges, and conducting flood - risk assessments over different sections of the river.

Bottom - Mounted (Fixed) ADCP

Bottom - mounted ADCPs are ideal for continuous, long - term river flow observation. Where permanent river conditions allow their installation, they may be placed on the riverbed to record data for decades. They are application for research on base flow, river flow long - term trends, and the impacts of environmental change on the river ecosystem.

Cableway ADCP

In some sections of the Kabul River, especially in mountainous regions with good infrastructure, cableway ADCPs are suitable. Suspended under a cableway, they can be carried across the river to sample flow at different positions, providing detailed knowledge of the characteristics of the river flow throughout its width. The method is beneficial for accurate measurement of flow in terrain that is challenging to access where other deployment methods can be cumbersome or risky.

Working Frequency

The chosen operational frequency for an ADCP determines the range and resolution of measurement. A 600 kHz ADCP is suitable for detailed measurements in confined sections of the Kabul River and study of intricate patterns near Peshawar, having relatively high-resolution information. An ADCP with greater range of 300 kHz can be appropriate for large - scale surveys of the river where broad coverage of river cross - section is required but with relatively lower resolution.

Brand Recommendations

World - leading ADCP brands include Teledyne RDI, Nortek, and SonTek, with high - quality products, advanced technology, and excellent reliability. For a cost - effective budget, ADCP manufacturer Chinese brand "China Sonar Panda ADCP" is also very good. Made of all-titanium alloy material, this "economy ADCP" is extremely durable and resistant to corrosion, well-suited to the harsh environment of the Soan River. Its high cost-effectiveness makes it within the budget of a range of users, from small-scale research projects in the vicinity to city-scale water management initiatives. To find out more, visit their website at https://china-sonar.com/.

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