Original Research
Integrated modeling of water resources in upper Indus basin during 1961 to 2013: an application of water evaluation and planning (WEAP)

Fozia Ramzan1* , Hafiza Saima Ali2, Hafiza Hira Iqbal1, Bism-e-Rabbi3


1. College of Earth and Environmental Sciences, University of the Punjab, Lahore, Pakistan 2. Department of Space Science, University of the Punjab, Lahore, Pakistan 3. Punjab University College of Informa


The author(s) declared that no grants were involved in supporting this work.



The study aims to evaluate the availability of water resources toward better irrigation practices in Indus basin. The climate parameters such as temperature and rainfall are employed to investigate the total inflows in the western rivers during 1961 to 2013; while water evaluation and planning (WEAP) model was used to elucidate the agricultural demands. Results of trend analysis illustrates that the total annual rainfall in the study area is increasing with an average of 50.3 mm per year. Despite of increase in annual rainfall, water demands are not being fulfilled due to high seasonal variations as it has been observed that 59.72% of the rainfall occurs only in three months, i.e., July, August and September. The model application concludes that the total irrigation water demand was 120.3 MAF in 1976; however, it has been increased up to 152 MAF in 2013. Appropriate integrated management of water resources is needed to solve the recent water oriented issues.   

Corresponding author: Fozia Ramzan *,

How to cite: Ramzan, F., Ali, H.S., Iqbal, H.H., Rabbi, B.E., 2016: Integrated modeling of water resources in upper Indus basin during 1961 to 2013: an application of water evaluation and planning (WEAP). Bulletin of Environmental Studies 1(4): 111-119.


Copyright © 2016 Ramzan, Ali, Iqbal, and Rabbi. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

Competing interests: The authors declare that they have no conflict of interest(s).

Edited by: Muhammad Arslan (UFZ, Germany)

Reviewed by: Saddam Akber Abbasi (Qatar, Doha) & Muhammad Iftikhar (CEES, Pakisan)

Received: 04/10/2016

Accepted: 10/01/2016

Published Online: 10/01/2016


Climate change is drastically affecting the water resources worldwide (Giang et al., 2012). Increasing concentration of greenhouse gases (GHG) in the atmosphere due to burning of fossil fuels along with other anthropogenic activities have been recognized as potential causes of the gradual changes in the climate. It has been established that the average temperature of earth surface has been dramatically increased which is further projected to increase by 0.9°C and 1.5°C by years 2020 and 2050, respectively (Hussain and Mumtaz, 2014). These changes are fundamental to manage water resource in integrated way to increase water productivity to feed exploding population. Increasing population directly exerts pressure on available water resources   and in future per capita water resources available may dropped sharply in different regions of the world. As per the stress-index, a country with less than 1000 m3 of freshwater per capita per annum is considered as water-scarce country; while the index lower than 500 m3 renders it to be in absolute water shortage situations (Brown and Matlock, 2011). Globally, 1.2 billion of the people do not  have access to the safe drinking water and this figure will increase from 2.7 to 3.5 billion by the end of 2025 (Fig. 1) if appropriate steps are not taken to mitigate the water scarcity problem (Mukheibir, 2010).


Pakistan, being an arid to semi-arid country, is highly vulnerable to spatial and temporal variability in climatic parameters. About 59% of the annual rainfall is due to monsoon rains; a dominant hydro-meteorological re-source for Pakistan  (Farooqi et al., 2005). According to the statistics of Global Change Impact Studies Centre (GCISC), approximately 60% of the land of Pakistan receives less than 250 mm of rainfall per year. Moreover, as majority of the rivers of country originate from Hindukush, Karakoram and Himalaya glaciers, increase in temperature causes faster melting of snow. This type of topography and climate change could affect monsoon dynamics and cause summer rainfall levels to drop. There may also be longer gaps between rainy season (Khan et al., 2010). Subsequently, variations in regions climate particularly in precipitation can cause disturbances in water resources leading to the food security issues. In addition, as country economy shares ~70% of the revenue from agricultural practices, management of its water resources is pivotal (Akhtar et al., 2008). Irrigation practices rely on the Indus basin system for domestic, agricultural and industrial needs. In comparison to the stress-index, as mentioned previously, Pakistan is striving with water scarcity as it has 1038 m3 per capita of water, which is expected to be reduced to 751 m3 per capita till 2030 (Sufi et al., 2010).

Precise estimation of water scarcity has always remained as a challenge to hydrologists worldwide. The understanding of local climate, glaciology, and runoff may provide comprehensive description of recent-past climate experiences {Archer, 2010 #3}. In this regard, different methodologies have been proposed among which population-water equation has been appeared to be an effective tool (Mukheibir, 2010). The current study aims to (1) evaluate the temporal changes in rainfall and runoff using trend analysis over the period of 1961 to 2013, and to (2) assess the availability of water resources using WEAP model for better irrigation practices in Indus basin, Pakistan.

Study Area

Upper Indus Basin (UIB) is a Trans- boundary catchment extending in the territories of Pakistan, Afghanistan, China and India.  The total surface area of the UIB is approximately 220,000 Km2 without including Tibetan Plateau′s rivers basin. The UIB extends from Tibetan plateau to northeast Afghanistan and is comprised of high Karakoram, Hindu Kush, and Himalayan mountain region. It also contains the vast area of perennial glacial ice outside the Polar Regions and the winter snow cover further increases its magnitude. (Mukheibir, 2010).

ArcGIS, a mapping tool and software was used to create different maps such as projected water scarcity areas of the world in 2025, study area and Digital Elevation Map (DEM) of Upper Indus Basin.

Materials and Methods

Data Collection

Total monthly rainfall and monthly mean temperature data was collected for the period of 53 years (i.e., 1961 - 2013) from Pakistan Meteorological Department (PMD), Lahore. The historical data on hydrological variables including total river inflows, canal withdrawals from each river, and water storages data in reservoirs and in Indus basin irrigation system (IBIS) was collected from water resources management division (WRMD), Lahore. The data on total agricultural land of Punjab (1980-2013) was collected from Punjab agriculture department (PAD), Lahore; and the data on total agricultural land of Sindh was obtained from the website of Pakistan Bureau of Statistics.

Trend Line Analysis

In semi-arid or arid regions, relatively small changes in temperature and precipitation may significantly changes runoff pattern (Gan, 2000). However, hypothesis testing for long-term trends of climate change and river inflows can help in determining the inherent mechanisms of a hydrological process. (Chen et al., 2006). The Total Annual Means Flows and Linear Trend Lines are calculated by using Microsoft Excel while standard deviations of data are found out by using SPSS statistics. To find out the relationship between rainfall and annual river inflows, regression analysis was carried out. Least square regression is a method for finding a line that summarizes the relationship between the two variables, at least within the domain of the explanatory variable x.

where b = slope of the regression line

a = intercept point of the regression line and the y axis.

 X = Mean of x values

Y = Mean of y values

 SDx = Standard Deviation of x

 SDy = Standard Deviation of y

Seasonal Variations in Rainfall

To calculate seasonal indices, components of the time series are supposed to follow the multiplicative model. The simple averages of the quarterly values over a long period of years are known as the seasonal averages. Resultantly, seasonal averages are converted into the percentages of the averages and represented as the seasonal indices as shown in below equation.

Seasonal variations in rainfall data were analyzed by the percentage of annual average method. In this method, first step is to eliminate the effect of the trends. For this purpose, we simply computed the annual averages and then divided each of the quarterly observation with the corresponding annual-averages. The results are expressed in percentages.

WEAP Modeling

The WEAP model was used to evaluate the water planning and management issues. It performs a balance between water supply and demand. All the elements of water demand-supply and their spatial relationships are included within the model. The whole system is characterized in terms of various water resources (freshwater and groundwater etc.), withdrawal, transmission and water demands (Yates et al., 2005).

For the WEAP analysis, the model sets up the spatial boundary, time frame, system components and configuration. The model can be run with any time step (daily, monthly and annually); however, an annually time step was used for the current study of Upper Indus Basin (UIB) (Hoff et al., 2007). Furthermore, time frame was set on the availability of accurate data on demand and supply with the modeling period of 38 years (1976-2013) (Musota, 2008).

Additionally, the WEAP model optimizes water uses in catchment through an iterative linear programming algorithm. The main objective is to maximize the water supply to demanded sites according to a set of priorities. When water is inadequate, the algorithm is formulated to limit allocation of water for those places given the lowest priority (McCartney et al., 2009). However, if site is connected to more than one supply source, then supply is ranked by using supply preferences. Generally, in WEAP modeling, freshwater is set to be with highest preference as it is more reliable and major source of water (Sanjaq, 2009).

The next step in WEAP modeling is mapping of water resources and demand sites and the connections among them (abstractions, discharge, and water transfer). Three rivers (Indus, Jehlum and Chenab), three reservoirs (Tarbela, Mangla and Chasma) and a demand site (Agriculture) were plotted in the schematic map. The transmission connections were drawn to represent the volumes of water diverting from the rivers of the Indus system to the canals.

After drawing schematic map, all required data was entered into WEAP software which can be entered manually or by linking Microsoft excel files. Annual data of all site, rivers, reservoirs and transmission links plotted in schematic map was entered. In WEAP, integrated hydrology was applied to examine scenarios in which the historic sequence of wet and dry years was not preserve. Additionally, the model can apply under different levels of drought that might be occur due to climate change (Purkey et al., 2008). After running and calibration the model;  calculated results were represented in both data and chart form (Mounir et al., 2011).


Changing Trends of Rainfall

During last 52 years (i.e., 1961 to 2013), a significant variation in rainfall pattern was recorded Figure 3. The linear trend line expresses that the rainfall in western rivers of Pakistan was increasing with the passage of time and the annual increase was ~50.285 mm (Fig. 3).

Furthermore, it was recorded that the mean inflows in rivers were dependent on annual rainfall. Water levels in rivers were significantly correlated to the annual rainfall (linear regression, p-value <0.05, adjusted R2 = 0.21; Fig. 4). The trend line describes that the change in rainfall patterns can positively affect the water inflows in rivers.

The seasonal variation in total rainfall in Upper Indus Basin (catchment areas of Tarbela, Mangla and Chasma) is given in Fig. 5. The data was analyzed by the percentage of annual average method. In upper Indus basin, 59.72% rainfall occurs only in three months (July, August and September) while remaining 40.28 % occurs in other nine months of the year. This indicates that there is flood period in third quarter (July, August and September) and dry period in the remaining months of the year.

Water Supply-Demand Gap for Irrigation (1976-2013)

Different parameters such as hydrology, agricultural area irrigated by the Indus river system, storage capacity of reservoirs, and river inflow were used to find out the supply-demand gap. Significant fluctuations in the total inflow of River Indus, Jehlum and Chenab at three large reservoirs Tarbela, Mangla and Chasma and below river heads were recorded (Fig. 6). High peaks in the graph show years of flood due to heavy rainfall; whereas, the low peaks show dry periods.

The total water storages of Tarbela, Mangla and Chasma reservoirs are given in Fig. 7. An irregular decrease in water storage was recorded during 1998 to 2013. The total minimum storage (~5.43 MAF) was recorded in 2004 and the maximum (~15.19 MAF) in 1983. Average total inflow in western rivers was129.62 MAF, but total storage was very low.

The total canal withdrawal from western rivers to agricultural lands of Indus Zone and Jehlum-Chenab Zone during the period of 1976 to 2013 is given in Figure 8. Blue line shows fluctuations in canal withdrawal from Indus Riverhead to Indus Zone; whereas, the red line is showing canal withdrawal into Jehlum-Chenab Zone on annual basis. The average withdrawal to both zones is recorded as ~97.91MAF.

The total water demand for irrigation purpose (during 1976 to 2013) is given in Figure 9. With the passage of time, demand of irrigation water has increasing continuously. Total demand of irrigation water was 120.34 MAF in 1976 but now it has been increased up to 152 MAF in 2013. The Fig. 10 represents unmet demand of irrigation water. The unmet demand of irrigation water in 1976 was 35.67 MAF while it increased up to 65 MAF in 2013.


Results showed that rainfall in Indus basin is highly concentrated temporally. About 60 percent rainfall occurs in monsoon summer season (Chang, 2004; Rakhecha and Pisharoty, 1996). There is significant variation within the monsoon season, including fluxes between heavy and low rainfall periods (Annamalai and Slingo, 2001; Singh et al., 2014). Resultantly, the rivers receive more inflows during heavy rainfalls, even overflow in some parts of the country. On the other hand, same regions receive very less rainfall in rest of the year. Therefore, the rainfall is presumed to be one of the major sources of river inflows (Reynard et al., 2001).

In Indian sub-continent, climate change and socio-economic variations are considered to have a great impact on available water resources (Biemans et al., 2013). Climate change is unavoidable and persistent naturally. However, in 20th century, it is supposed to be linked with anthropogenic activities such as urbanization, emission of greenhouse gases and the burning of fossil fuels (Klein et al., 2014). In turn of climate change, an increase in extreme events of rainfall in South Asian countries has been forecasted (Solomon, 2007).

Heavy rainfall looks like an antidote to the water scarcity, but it might not be the solution, and can lead to severe landscape hazards (Hewitt, 1983). Furthermore, heavy precipitation over a short period of time may lead to flooding that cause environmental, social and economic distraction. Climate change has imposed negative impacts on the rainfall systems of the country, mainly by demolishing the seasonal rainfalls and/or modifying its intensity (Naheed et al., 2013).

The agriculture of Pakistan mainly depends on a single source, the Indus system (Archer et al., 2010; Qureshi, 2011), which comprised of six major tributaries: the Indus, Chenab, Jhelum, Ravi, Beas, and Sutlej. The Upper Indus Basin is very developed watershed, with large physical infrastructure. The irrigation system is the largest demand site and in many ways the most significant and complex one (Archer et al., 2010; Qureshi, 2011). The hydrological balance of the Indus basin will shift as the global climate changes (Immerzeel et al., 2010), however to what extent is yet unclear. Results obtained from the WEAP model showed that the unmet water demand increased dramatically because of limited supply and growing population size. Although the monsoon precipitation in summer not only caters the power supply demands but also fulfills the water demands in agricultural sector, it cannot fulfill in long run. Similarly, snow and glacier melts over the northern also contributes to sustainable river flows for irrigation. Still the country is facing drought like conditions (Altaf et al., 2009; Qadir et al., 2007). It is suggested that the water shortage will lead to the food shortages in Pakistan. By 2025, the estimated shortfall of water will be ~32%, which may result in a food shortage of about 70 million tons (Qureshi, 2011). 

It is therefore, the urgent surface water management is required. Water management agencies should develop adaptive strategies that can effectively manage water resources in light of climate change. Pakistan is facing both floods and drought like situations due to lack of water reservoirs.   Seasonal variability in rainfall could be managed by constructing several dams that can store the water and prevent the flooding and landscape hazards. These dams will also be helpful to cater the water crises in agricultural sector. The old water management plans which have been failed to solve water scarcity issues. Thus, there is need to develop IWRM plan and its effective implementation.

The second possible option for water management is to introduce and adapt water efficient agricultural practices. For instance, in Pakistan, rice is very common cereal and requires a lot of water. We can shift from conventional flooded rice to aerobic rice system (Awan et al., 2015). Similarly, the latest water efficient techniques such as drip irrigation (Deveci et al., 2015) and sprinkler irrigation (Evans et al., 2013) can be adopted. Furthermore, grey water can be utilized efficiently in gardening as well as agriculture after suitable treatment. 

The country receives heavy rainfalls in monsoon season while dry conditions prevail in remaining months.  Therefore, the current water issues can be solved by proper and integrated management of water resources. To integrate the available water resources, a series of dams are needed, in such a way that river flows are tamed in steps and reservoirs are managed as a cascade.


It is concluded that the water demands of Pakistan are increasing continuously, whereas the supply is going down drastically. Climate change is significantly affecting the water resources by changing the rainfall patterns as well as glaciers and snow melting. As the result, Pakistan is facing flooding and droughts simultaneously. At the moment, Pakistan is water stressed country but could be included in water scars countries in upcoming decades. Thus, there is an urgent need to develop IWRM plan and its effective implementation.


Compliance with ethical standards

Conflict of Interest

The authors declare that they have no conflict of interests.


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