Estimating Sectoral Water Demand for Sindh Province of Pakistan

Water resources in Sindh province of Pakistan are under significant pressure due to increasing and conflicting water demand from municipalities for domestic users, agriculture and industries, and requirements of environmental flows. Population growth and climate change are likely to pose serious challenges to households and economic sectors that depend on water. This study estimates the present water demand from municipalities, agriculture and industries, and its future projections by the year 2050 in Sindh. The study also evaluates the impact of climate change on sectoral water demand and assesses the water requirements for the environmental flows. The results show that presently the total water demand for these sectors in Sindh is 44.06 Million Acre Feet (MAF). Agriculture is the largest consumer of water, accounting for 95.24 percent of the total water demand. Municipal water demand accounts for 2.61 percent while industrial water demand accounts for 1.88 percent. The demand for water in these sectors is expected to rise by 10 percent from 2018 to 2050. Moreover, depending on climate change scenario, the total water demand in these three sectors is likely to rise by 16 to 25 percent from 2018 to 2050. In additions, water requirements for the environmental flows have been indicated as 10 MAF in the National Water Accord of 1991. The findings of this study call for policy measures and strategies for management of water resources in Sindh.


INTRODUCTION
ith a population of nearly 50 million, Sindh is the second most populous province in Pakistan. Its economy accounts for more than one third of economy of Pakistan. Sindh is the most downstream province in the Indus River Basin and depends almost exclusively on the water resources of the Indus River. Users of water resources include municipalities for domestic users, agriculture, industries and environment. Agriculture, which accounts for almost 20 percent of GDP and 70 percent of employment in Sindh, has traditionally been the largest user of water resources 1 Professor of Economics, IBA, Karachi, Sindh, Pakistan. Email: hlohano@iba.edu.pk (Corresponding Author) 2 Member, Higher Education Commission, Islamabad, Pakistan. Email: fateh.marri@hec.gov.pk [1]. Water resources in the province are distributed through the Indus Basin Irrigation System (IBIS), which comprises three main barrages on the Indus River in Sindh. These barrages divert water into fourteen main canals that serve a total cultivable command area of 6.8 million hectares [2].
Undoubtedly, the Indus River system has shaped the economic development of Sindh, and has delivered critical water services. However, water resources in Sindh -as in the larger Indus Basin -are under significant pressure, a situation which is likely to be exacerbated by climate change. This has also been underscored at the country level in National Water Policy of Pakistan [3]. Under the framework of the national water policy, each province including Sindh W Estimating Sectoral Water Demand for Sindh Province of Pakistan is required to develop its own water resources management plan keeping in view the challenges facing the province. Water use sectors are generally categorized into four sectors, namely municipal (domestic users), agriculture, industry, and environmental flows. Three users of water including municipal, agriculture and industry place their demand for water, while the environmental flow is the water required for ecosystem, which provides various ecosystem services.
Due to diverse geography of Sindh and conflicting water demands, climate change and weather variability are likely to create a great deal of uncertainty about water sector and pose serious challenges to economic sectors that depend on water. Sindh is very vulnerable to climate shocks due to its geographic location. It is already a hot region with mid-summer temperatures shooting as high as 50 o C in some regions, so further increases in temperature can be very detrimental to crops and lives in form of heat waves. Sindh being the lowest riparian province is at high risk of droughts and floods in case of relevant water activity upstream. Thus, there is a need to estimate water demand to input for formulating policies and developing strategies that would facilitate managing water resources and climate change adaptation in Sindh to mitigate the negative impacts of climate change on the water sector.
The main objective of this study is to estimate the present water demand from municipalities, agriculture and industries, and its future projections by the year 2050 in Sindh. The study also evaluates the impact of climate change on sectoral water demand and assesses the water requirements for the environmental flows.

METHODOLOGY
To estimate the sectoral water demand, this study uses secondary data and various analytical methods including descriptive analysis, regression analysis and past trend analysis. Furthermore, this study uses the parameters estimated in the literature and also estimates some other parameters using secondary data. Based on the nature of the sector, appropriate data and methods are used for estimating the water demand separately for each sector including municipalities, agriculture and industries. The details about data, methods and assumptions for estimating and forecasting water demand for each sector are given in the following section along with the results. The requirements for environmental flow are assessed by reviewing the literature including National Water Accord 1991.

Water Demand Projections and Climate Change Impacts
In this section, we analyze and forecast the sectoral and total demand for water and potential climate change impacts on water demand. We also assess the water requirements for environmental flows.

Municipal Water Demand
Water demand from municipalities for domestic users depends on several factors including population, proportion of urban and rural population, and climatic conditions. Table 1

Agricultural Water Demand
Agriculture sector includes not just crops but also livestock, fisheries, agro-forestry and rangelands [7]. We estimate the agricultural water demand using data of both surface water and groundwater. Total agriculture water is calculated by adding the water availability at farm gate and the groundwater used by agriculture sector. To estimate the demand for agriculture water in Pakistan, we estimated a trend line of total agriculture water by regressing the natural log of agriculture water on time using data for past 21 years. The upward trend was statistically significant at 10 percent level. The regression results show that agricultural water use has increased at the rate of 0.16 percent per annum in the past 21 years, which we use to compute future projections for 2030 and 2050.  of water at farm gate and groundwater use for Pakistan are available in Statistical Year Book [9]. As data on canal water withdrawal was available for both Pakistan and Sindh, we estimated water at farm gate for Sindh assuming that the ratio of farm gate to canal water withdrawal is the same in Pakistan and Sindh. Table 3 shows that, during last ten years, Sindh's share was 40.54 percent in surface water at farm gate and 16.24 percent in groundwater. Overall, Sindh used 31.57 percent of total agricultural water in Pakistan. We compute the future projections of total agricultural water demand for Sindh assuming that the growth in water demand in Sindh will mimic the pattern in Pakistan and Sindh will require 31.57 percent of total agricultural water demand of Pakistan.

Industrial Water Demand
For estimating the industrial water demand in Pakistan, we assumed water requirement per rupee of industrial value addition in GDP in 2008. Data on industrial water withdrawal in 2008 were collected from AQUASTAT [10] while data on industrial value addition in GDP were collected from Pakistan Economic Survey reports [7; 11]. For future projections of industrial value addition in GDP, we used its average growth rate (3.74 percent) during 2007-08 to 2017-18. For estimating the industrial water demand in Sindh, we estimated the water share based on Sindh's share in industrial value addition in GDP of Pakistan, which was 42.2 percent in 2012-13 according to Pasha [12]. For future projections, we assume that Sindh's share in industrial value addition in GDP of Pakistan will remain the same.   The industrial water demand in Pakistan in 2050 attributable to climate change shows that the industrial water demand will increase by 11.8 percent under the climate scenario of 1°C and by 23.5 percent under the climate scenario of 3°C. This shows that under the climate change regime, it is expected that the industrial water demand will be even higher. We find that if the temperature increases by 1°C, then the industrial water demand in Pakistan will rise from the existing demand of 2.08 MAF (in 2018) to 6.82 MAF in 2050. Similarly, the industrial water demand in Sindh will rise from the existing demand of 0.88 MAF (in 2018) to 2.60 MAF in 2050. If the average temperature increases by 3 °C in 2050, it will put more pressure on the current water resources of the country. Under this scenario, the industrial water demand is expected to rise to 6.82 MAF in Pakistan and 2.88 MAF in Sindh in 2050. We find that if the temperature increases by 1°C, then the total water demand in Sindh will rise from the existing demand of 44.06 MAF (in 2018) to 51.23 MAF in 2050, which 16 percent increase. If the average temperature increases by 3 °C in 2050, it will put more pressure on the current water resources.

Water Requirements for Environment
Environmental flows for escapage to sea are the most important for sustaining ecosystem and minimizing the losses due to sea intrusion. Low environmental flow has threatened the mangroves, disturbed the ecological balance and created extreme hardship for the fisher folks and other communities residing in the Indus delta and near the coastline. Furthermore, maintaining a continuous flow throughout the year in downstream of Kotri Barrage is critical for sustaining the ecosystems of the Indus Delta [13] The National Water Accord of 1991 [14] recognized the need to ensure a minimum environmental flow below Kotri for escapage to sea. The proposal of a minimum 10 MAF for environmental flow was discussed at length. However, as the other studies have suggested more/less than 10 MAF as a minimum environmental flow each year, it was decided in the accord that further studies would be conducted to determine the minimum environmental flow below Kotri for escapage to sea [14]. Thus, Sindh needs to meet the water demand not only from the municipal, agricultural and industrial sectors but also for the environmental flows for sustaining the ecosystem in the Indus delta.

Challenges of Water Resources Management
The sectoral water demand analysis given above shows that due to population growth, urbanization and climate change, the demand for water will increase in future.
The ecosystem of Indus Delta has already been degraded as discussed above and the situation can further be aggravated with continuous increase in water demand from other sectors and due to climate change. In order to ensure adequate water for the three economic sectors and for the environment and ecosystems including wetlands, mangrove forests and irrigated forestry, substantial quantity of water will be required in Sindh.
Historically, groundwater use has been increasing to meet part of the increasing demand. However, there are limitations of groundwater due waterlogging and salinity issues in Sindh and declining water table across the country. Thus, there will be immense Estimating Sectoral Water Demand for Sindh Province of Pakistan pressure on the Indus river water from different sectors.
To ensure food and water security and protection of environment and ecosystems, Sindh needs to develop integrated water resource management (IWRM) plan that not only has the sectoral water demand management plan but also the plan for increasing water supply by reducing the water losses in the Indus river system and exploring rain harvesting.
The overall water efficiency in the Indus River system in Sindh is only 35 percent, indicating huge water losses [15]. Furthermore, total water productivity in Pakistan is very low -USD 1.38 per cubic meter of water. Pakistan ranks eighth lowest in the world in terms of total water productivity [13]. Agriculture sector is using water inefficiently. Despite using 95.24 percent of total water, there is a lot of farmland uncultivated mainly due to unavailability of water. Total cultivated area in Sindh is 5.198 million hectares while culturable waste is 1.607 million hectares, most of which is not cultivated due to water shortage [2]. Similarly, there is a limited access to safe and reliable water for household and industries.

Impact of Adaptation Investment
A study by the World Bank [15] evaluated the impacts of adaptation investments in Pakistan. The results are presented in Table 7. They evaluated three adaptation investment options (i) investments in agricultural technologies to increase crop yield (such as developing new seed varieties), (ii) investment for canal and watercourse efficiency improvements, and (iii) construction of new reservoirs to introduce an additional 13 MAF.

CONCLUSION
The sectoral water demand analysis of municipalities, agriculture and industries shows that due to population growth, urbanization and climate change, the demand for water in Sindh is expected to increase substantially in future. Depending on climate change scenario, the total water demand in these three sectors is likely to rise by 16 to 25 percent from 2018 to 2050. Furthermore, the environment and ecosystems require minimum annual water flow as well as a continuous flow throughout the year in downstream of Kotri Barrage for escapage to sea. This shows that substantial quantity of water will be required in Sindh for the three economic sectors, environment and ecosystems.
For food and water security and protection of ecosystem, Sindh needs to develop integrated water resource management (IWRM) plan that not only has the sectoral water demand management plan but also the plan for increasing water supply by reducing the water losses in the Indus river system and exploring rain harvesting. In the following sections, we present the way forward.

RECOMMENDATIONS
The findings of this study call for policy measures and strategies for management of water resources in Sindh, with focus on integrated water resources management (IWRM) plan, water demand management and conservation, investment in infrastructure and technology, and water information management.
Integrated water resources management aims to achieve economic efficiency as well as equity among all users of water. Since all water users are competing for water share, it is very important to encourage a multi-sectoral approach rather than focusing on single sector only. Integrated waters resources management is a framework of interrelations between sources of water, its uses and better stakeholder engagement. It is a holistic and participatory approach to decision making spanning the entire watershed, management and development of resources such as land, water and related assets. This plan would require policy framework for institutional reforms, capacity building,  [15] review of water pricing, spatial water distribution, improving water productivity and water efficiency, investment in infrastructure and technology adoption, raising awareness, and participation of all relevant stakeholders.

Estimating Sectoral Water Demand for Sindh Province of Pakistan
Sindh needs to develop policies for water demand management and conservation to ensure food and water security and protection of ecosystem. Policy makers are increasingly recognizing the need for consideration and implementation of water demand management. For example, recently, Government of Sindh has imposed a ban on rice cultivation in some parts of Sindh along Ghotki feeder, Rohri canal and Nara canal, as rice crop not only uses high amount of water but may also cause waterlogging, salinity and land degradation in some type of soils. Water demand management is required for all sectors but most of the contribution for saving water is expected from the largest user of water, that is, agriculture sector. Investment in Infrastructure for Access to Safe Water by Households: Households place a high value for access to safe water and are willing to pay for better quality of water and reliable access to piped water [16]. There is a limited access to safe water for household. Around 33 percent of households in Sindh use hand pump as the main source of drinking water while majority of households in rural areas of Sindh (63 percent) use hand pump as the main source of drinking water [17]. Sindh needs to give priority to domestic use of water and charge water tariffs to ensure maintenance of the infrastructure.
Sindh can save a lot of water by making investments in improving canal and watercourses. More food and fiber products can be produced with development of agricultural technology and new seed varieties and breeds that give higher yields and are water efficient, drought tolerant and salinity tolerant.
The investments in water informatics can assist in timely alerts for flood management, information of flow at barrages, optimum water escape to sea and timely weather forecasts through SMS and other channels to farmers, households, business community and other stakeholders.