Securing the Drinking Water Supply for the Growing Population of City, CASE STUDY 29 Case Study 29 Securing the Drinking Water Supply for the Growing Population of Xiamen City, PR China

Nengwang Chen* and Huasheng Hong

Coastal and Ocean Management Institute Key Laboratory of the Coastal and Wetland Ecosystems, 422 South Siming Road, Xiamen, Province, PR China

Key Message Abstract

• Effective management of freshwater This case study is aimed at demonstrating resources across local (subnational) an ongoing comprehensive and science- administrative boundaries requires based water supply management initiative not only close cooperation and to determine the amount and quality collaboration of concerned local of safe drinking water for the growing governments and line agencies but population of Xiamen City and other also the support of academic and sub-urban areas. Also highlighted are research institutions. Such institutions the integrative approaches in water can provide needed scientific data and management of the system water quality monitoring information especially in coordinating the relevant for appropriate public investments and cross-boundary municipalities, agencies, interventions in terms of water supply and users. The case study underscores policy and management measures. the importance of science in assisting management decisions particularly in • In securing continuous freshwater water quality monitoring, water safety supply to meet the growing population and allocation across boundaries, as well demand, scientists in Xiamen as in information management. It also This section is part of the book: collectively demonstrated their elaborates the need to improve the existing Chua, T.-E., L.M. Chou, G. Jacinto, indispensable role in water resource methodological approach to increase S.A. Ross, and D. Bonga. (Editors). 2018. Local Contributions to Global management decisions. scientific reliability in prediction modeling. Sustainable Agenda: Case Studies in Lessons learned from water supply Integrated Coastal Management in the East Asian Seas Region. Partnerships management initiatives are also presented. in Environmental Management for the Seas of East Asia (PEMSEA) and Coastal Management Center (CMC), Quezon City, Philippines. * Email: [email protected] 337 CASE STUDY 29

Background dam construction can drastically change river hydrology and biogeochemistry and Main issues of drinking water supply thus create negative impacts on the river for coastal cities ecosystems (Kelly, 2001; Vörömarty, et al., 2003). One of the most direct consequences Global population is set to increase for cities located downstream is the reduction dramatically within the next 30 years, up to of freshwater supplies from the upper reaches a staggering 9.6 billion by 2050 (UN, 2013). of major rivers. With a great majority of the population residing in coastal cities, particularly in In the context of increased human and developing countries (Lutz and Samir, 2010), climatic perturbations, freshwater supply— the demand for clean and safe drinking water or the lack thereof—is already an urgent supply would be a key challenge to sustaining coastal management challenge. The lack the urban population. Most developed coastal of scientific understanding of pollutant cities lack freshwater resources largely due emission and transport, limited investment to relatively limited water catchment areas. in pollution mitigation, and inadequate In China, many cities have to rely on water monitoring of water quality continues to supply from adjacent inland watersheds. Such hinder the sustainable management of a situation often gives rise to transboundary water resources (Jia, et al., 2010). The lack distributional challenges, affecting both of comprehensive data on watershed-river- quantity and quality of water. reservoir and on quantity and quality of receiving waters in urban coastal areas also Unregulated human settlements and severely affects the effectiveness of the design economic activities within a watershed and implementation of water resources area are often found to degrade the quality management programs. For rapidly developed of freshwater resources. Overfertilization coastal cities like Xiamen, availability of of agriculture farms and discharges from appropriate scientific information and animal and domestic wastes, which are often management tools was essential to address inadequately treated, lead to nutrient (mainly freshwater resource management concerns, nitrogen [N] and phosphorus [P]) enrichment especially those across administrative in receiving waters; often resulting in boundaries. eutrophication and algal blooms. In addition, persistent organic pollutants (POPs), heavy Geophysical characteristics of Xiamen metals, and other pollutants from both point and water supply challenges and diffused sources, threaten water security for coastal city populations. Xiamen, historically known as Amoy, is a major city on the southeast ( Strait) Furthermore, a large number of dams have coast of Fujian province, the People’s Republic been constructed worldwide (China included) of China. Xiamen has an area of 1,699 km2 along river channels for hydropower and a population of 3.81 million by the end generation, flood control, irrigation, and to of 2014 (XBOS, 2015). Xiamen comprises a certain extent, for tourism development Xiamen Island, Island, and part of (Miao, et al., 2015). However, intensive the rugged mainland coastal region from the

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Figure 1. Jiulong River Basin showing various monitoring sites. Arrow shows water transfer from source (Jiangdong reservoir in the southern part of North River) to Xiamen City.

left bank of the Jiulong River in the west to the Xiamen has a monsoonal subtropical climate, islands of Xiang’an in the northeast. It borders characterized by long, hot, and humid summers City to the north and and short, mild, and dry winters. Typhoons City to the west. The city previously centered normally occur in late summer and early on Xiamen Island but expanded to include four autumn. The annual rainfall is 1,350 mm. other districts: Haicang, Jimei, Tong’an, and However, rapid urbanization, population Xiang’an on the mainland. growth, and climate change in recent years

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were posing water supply challenges to Current scientific knowledge meeting increasing demand for safe and clean and management implications drinking water. Total water supply increased sharply from 295 to 419 million m3 in 2009– Climate change and its impact on water 2014 (XBOS, 2010, 2015). Furthermore, resource availability the majority of water supply was from the Jiulong River rather than a local source. The Based on a 50-year (1960–2009) daily dataset Jiulong River is the main river system running of temperature and precipitation at two through several districts before entering national meteorological stations (Xiamen Xiamen coastal seas. It provides Xiamen City and Zhangzhou), the characteristics and 168 million m3 of water per year through a long-term trends of climate change were transport tunnel that was constructed in 1972 analyzed using the Piecewise Linear Fitting (Figure 1), accounting for over 80% of the total Model (PLFM) (Tomé and Miranda, 2004). water supply. Other major water sources for The results showed that the annual mean suburban area are Tingxi reservoir and Bantou air temperature at Xiamen and Zhangzhou reservoir located north of Xiamen Island. generally increased from 1960 to 2009 by 0.225°C and 1.475°C, respectively. The “warm Three tributaries (North River, West River, and winter” phenomenon was especially evident South River) discharge water into . in the last 30 years. Precipitation at Xiamen The North Jiulong River is the main tributary and Zhangzhou showed overall increases with a drainage area of 9,570 km2 and a mean during summer. However, precipitation annual discharge of 8.23×109 m3. The length decreased significantly by 20% in the last of the main tributary to the water intake decade (Figure 2). The occurrence and point at Jiangdong is about 274 km. Land use intensity of extreme climate events such as includes 78% forest (mostly secondary), 16% hot day (>99%), storm day (daily rainfall arable land, 3% urban and residential land, > 50 mm), and drought day (without any 2% water, and 1% bare or grassland (2007 rainfall) significantly increased. The climate Landsat Thematic Mapper image). Over 100 in these two areas showed a general trend of hydropower dams were constructed within the “warm and dry” in winter, but with increasing Jiulong River Watershed (Wang, et al., 2010). rainstorms in the summer. Given the close link between climate and hydrology, the Four cities/counties ( City, climate change trends were likely to pose County, Hua’an County, and Changtai County) adverse impacts on water resource availability and a part of Zhangzhou City are located in to Xiamen City due to the increased seasonal the watershed area. The total population is and interannual variation. Such analysis 1.5 million, 43% of whom live in the urban provided a basis for developing adaptive areas. Longyan City, which is located in the management strategies in response to climate upstream area, recently experienced a rapid change in the region. increase in animal farming activities. The other counties are predominantly covered Nutrient enrichment and eutrophication with agricultural and forest land, and relatively (algal bloom) threaten water quality of low population with the exception of the more densely populated Changtai County and Increasing human activities and external Zhangzhou City in the downstream area. nutrient loads over the past 30 years were the main causes of water degradation and

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Figure 2. Precipitation trends in Xiamen and Zhangzhou (1960–2009).

eutrophication (Chen and Hong, 2012; Chen, However, phytoplankton communities change et al., 2013). A significant decline of N:P ratio seasonally, associated with river discharge, was observed in both river and estuarine irradiance, water temperature, and nutrient waters since the 1990s due to relatively high P concentrations (Tian, et al., 2014). The local loadings, a consequence of waste discharges government was informed by scientists of from the proliferating husbandry of livestock the perils of nutrient pollution. A number of and the application of excessive phosphate management initiatives were implemented fertilizers to cash crops. Continued nutrient since the late 1990s with limited success due enrichment and decline of N:P ratio changed to the lack of holistic planning and integrative the nutrient stoichiometry and supply ratio in management measures given the complicated waters, in turn increasing the risk of nutrient- socioeconomic and political situation in PR enhanced algal blooms. According to current China (Peng, et al., 2013). findings on eutrophication and harmful algal bloom processes, a dual nutrient (N and P) management strategy was necessary to manage the water quality in the Xiamen Bay-Jiulong Approach and Methodology River Basin. Focus needed to be on reducing animal wastes in the north Jiulong tributary and Developing a watershed water mitigating overfertilization in the west Jiulong information system tributary (Chen, et al., 2013). A water security program was initiated in 2009 Three algal bloom events were monitored and completed in June 2012. It addressed key in the north Jiulong River since 2009, which drinking water issues, including contamination threatened Xiamen’s drinking water supply. at source. Funded by the Xiamen government, The main reason for the algal blooms was the Jiulong River Watershed Information the excessive nutrient loading from human System (JRWIS) was developed by Xiamen and animal wastes, and agricultural runoff University in collaboration with Fujian Strong accumulated in dam reservoirs with limited Software Company and Xiamen Environmental removal (Li, et al., 2011; Chen et al., 2014). Monitoring Central Station.

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The JRWIS included a multisource database accessible to other related agencies such as the (meteorological data from 10 stations, North River Water Transfer Office, the Xiamen hydrological data from 7 stations, water quality Water Affairs Group, and environmental data from 11 provincial control stations, monitoring stations in upstream cities (e.g., and 4 automatic water quality stations) Longyan, Zhangzhou), as well as the provincial based on SQL2005 and ArcSDE, using Web Environmental Monitoring Central Station in Geographic Information System, remote City. sensing, and GPS technology. A coupled model (SWAT+EFDC+WASP) was also integrated into The JRWIS was the first effort in China to JRWIS to simulate river discharge and water develop a robust, comprehensive, and fully quality (e.g., ammonium, total nitrogen [TN], coordinated surveillance and monitoring total phosphorus [TP], dissolved organic P, and system for water quality. The main applications chemical oxygen demand [COD]). The spatial of JRWIS included: database included administrative maps, remote imagery, digital elevation model (DEM), soil 1. Water quality parameters (e.g., dissolved map, and land use/cover. Monthly water quality oxygen, pH, nutrients, chemical oxygen monitoring data was easily imported, while demand, and chlorophyll) could be in-situ sensor data from buoys and automatic monitored through data query and monitoring stations were transferred and plotted. Users easily assessed the water imported to the database in real time. Discharge quality situation and spatial and temporal data (flow rate) released by the China Ministry variations. Real-time data over the previous of Water Resources and rainfall/temperature/ 24 hours were shown at the touch of the wind data released by the China Weather screen. Bureau were also linked to JRWIS. In this setup, the database of JRWIS could be easily updated. 2. Timely and accurately prepared evaluation reports of water quality, including monthly, The JRWIS provided various function modules, seasonal, and annual variation could be including data acquisition, data management accessed. National or local water quality and editing, data query and plotting, map query, criteria were also incorporated, and an water quality assessment, early warning of water evaluation could be made based on various quality, and model simulation. The JRWIS was templates. According to users from the provided with a user-friendly interface and Xiamen Environmental Monitoring Center visualization screen, which made it a useful tool Station (XEMCS), JRWIS was much for improving water resource management. better in terms of data accuracy, time, and efficiency compared to traditional manual approaches. Results 3. An unhealthy water quality could be The JRWIS was installed in April 2011 detected before reaching the distribution and operated and managed by the Xiamen system. This enabled the concerned Environmental Information Center. It was a agency to alert the public and undertake Web-GIS system that enables users to log in and appropriate remedial measures. A case in use the system anywhere and anytime provided point was an incident detected by scientists that there were available Internet access from XEMCS using the information from and computer services. The system was also JRWIS. They noted that values of dissolved

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Figure 3. Model output shown on the JRWIS. A coupled model (SWAT+EFDC+WASP) was integrated into JRWIS to predict water quality. (This modeling work was completed by Dr. J. Huang of Xiamen University.)

oxygen (DO), pH, and chlorophyll from an important information was delivered to automatic monitoring station (Jiangdong the North River Transfer Office and the reservoir) kept rising from the afternoon Xiamen Water Affairs Group. The manager of 13 March 2013 until the next morning. of the North River Transfer Office decided Recorded data showed that DO had gone to increase dam outflow to mitigate an algal up to 21.22 mg/L, pH rose to 9.96, and bloom. A total of 3 million m3 of water was chlorophyll content reached 119.6 mg/m3 discharged on 14 March (1900-2100H), and (a typical set of conditions for a possible another 520,000 m3 on 15 March (1830– algal bloom). The scientists checked 1900H). Following these interventions, the data from three other automatic water quality recovered, meeting the monitoring stations (Xipi, Punan, and national water criteria. The coupled model Luobin) in the upper reaches and found (SWAT+EFDC+WASP) simulated river that a nearby station (Luobin, located in runoff and water quality to verify and assist a tributary close to Jiangdong) also had a management in deciding the release of dam high chlorophyll value of 55 mg/m3. This water (Figure 3).

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River to include other major water sources like Lessons Learned the Tingxi, Bantou, and Lianhua Reservoirs in Northern Xiamen. With a growing database, the Given the complex ecological processes information system will be further enriched. occurring in each aquatic ecosystem and the diverse socioeconomic conditions, The initiative of the Xiamen City government interdisciplinary research and model prediction reflected much needed cross-boundary have become essential to provide scientific cooperation and collaboration with concerned information that will be useful for effective local governments and line agencies as well water management. The JRWIS initiative was as expertise from academic and scientific the first step in the right direction. institutions in developing the database and information system. These efforts helped in The JRWIS was proven to be a useful science- the administration of appropriate management based information system which could serve as measures. The local government has good an interactive platform available for a variety experience in application of a holistic and of users to monitor and manage water quality. integrative management approach in addressing It was flexible in configuration so that users coastal management challenges and the capacity could add monitoring station(s) and data, to continue building the information system. when needed. However, accurate and highly precise measurements, expanded monitoring This case study also demonstrated a working coverage coupled with high precision modeling model for scientists to contribute to the process were still needed to strengthen more effective of policy and management decisionmaking assessments. by providing reliable information and sound scientific advice. At present, automatic measurement of water quality is limited to (a) a few monitoring stations (only four stations in such a large catchment); (b) a few parameters (TN, TP, References ammonium, COD, etc.); and (c) limited monitoring frequency (every four hours for Chen, N.W. and H.S. Hong. 2012. Integrated TN and TP). Current national criteria for Management of Nutrients from the water quality do not cover other important Watershed to Coast in the Subtropical contaminants (e.g., pathogenic microorganisms, Region. Current Opinion in Environmental emerging pesticides, veterinary drugs, and Sustainability, 4(2): 233-242. other POPs) that also threaten water quality and human health. There is a lack of precise Chen, N.W., Z.H. Chen, Y.Q. Wu, and A.Y. Hu. bathymetry data which are necessary for 2014. Understanding Gaseous Nitrogen developing a high-precision hydrodynamic Removal through Direct Measurement of

model. In addition, several key coefficients Dissolved N2 and N2O in a Subtropical River- for model input parameters have not been Reservoir System. Ecological Engineering, validated because of limited biogeochemical 70:56-67. observations. Hence, further work is necessary to ensure that predictive models can contribute Chen, N.W., B.R. Peng, H.S. Hong, N. more effectively to management decisions. The Turyaheebwa, S.H. Cui, and X.J. Mo. 2013. JRWIS should be further expanded from North Nutrient Enrichment and N:P Ratio Decline

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in a Coastal River-Bay System in Southeast Tomé, A.R. and P.M.A. Miranda. 2004. China: the Need for a Dual Nutrient (N & Piecewise Linear Fitting and Trend P) Management Strategy. Ocean and Coastal Changing Points of Climate Parameters. Management, 81:7-13. Geophysical Research Letters, 31(2), doi: 10.1029/2003GL019100. Jia, J.S., Y.L.Yuan, C.Y. Zheng, and Z.L. Ma. 2010. Dam Construction in China: Statistics, UN (United Nations). 2013. World Population Progresses and Concerned Issues. Water Projected to Reach 9.6 Billion by 2050 – Power, 36:6–10. UN report. Available at http://www.un.org/ apps/news/story.asp?NewsID=45165#. Kelly, V.J. 2001. Influence of Reservoirs on VVEOCY5Viko (Accessed on 11 May 2015). Solute Transport: a Regional-scale Approach. Hydrological Processes, 15:1227-1249. Vörömarty, C.J., M. Meybecsk, B. Fekete, K. Sharma, P. Green, and J.P.M. Syvitski. Li, Y., W.Z. Cao, C.X. Su, and H.S. Hong. 2011. 2003. Anthropogenic Sediment Retention: Nutrient Sources and Composition of Recent Major Global Impact from Registered Algal Blooms and Eutrophication in the River Impoundments. Global and Planetary Northern Jiulong River, Southeast China. Change, 39:169-190. Marine Pollution Bulletin, 63:249-254. Wang, G., Q. Fang, L. Zhang, W. Chen, Z. Chen, Lutz, W. and K.C. Samir. 2010. Dimensions of and H. Hong. 2010. Valuing the Effects of Global Population Projections: What Do We Hydropower Development on Watershed Know about Future Population Trends and Ecosystem Services: Case Studies in the Structures? Philosophical Transactions of the Jiulong River Watershed, Fujian Province, Royal Society B, 365(1554):2779-2791. China. Estuarine, Coastal, and Shelf Science, 86:363-368. Miao, C., A. Borthwick, H. Liu, and J. Liu. 2015. China’s Policy on Dams at the Crossroads: XBOS (Xiamen Bureau of Statistics). 2010. Year Removal or Further Construction? Water, Book of Xiamen Special Economic Zone- 7(5):2349-2357. 2010. China Statistics Press, , China.

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