3) Waste Water Collection Pipeline in Beichuan Zone
4.1 Current Situation of Water Resources in Xining .1 Basic Situation of Water Resources.1Basic Situation of Water Resources
Xining is located in the upper middle reaches of Huangshui River Basin and the river system of the whole city is mainly composed of Huangshui trunk stream and such branches as Beichuan River, Nanchuan River, Shatangchuan River, Yaoshui River and Xinachuan River. The total amount of water resources of the whole city is 1.314 billion cubic meters. The total amount of surface water resources is 1.293 billion cubic meters; the total amount of underground water resources is 894 million cubic meters; and the repeated amount is 873 million cubic meters. The river system of the project area is shown in Figure 3.1-2.
The special terrain and landform as well as the social and economic development of Xining have resulted in the following characteristics of water resources:
First of all, imbalanced water availability and a severe water shortage in the city.
The total amount of water resources in Xining accounts for 2.1% of that of the whole province. The per capita amount of water resources is about 600 cubic meters accounting for nearly 1/4 and 1/20 of those of the whole nation and the whole province respectively making it a resource-oriented city with serious shortage of water. Moreover, there is a relatively large gap in the distribution of water resources in each region of the city. Datongbaoku River and Dongxia River are important sources of water resources of Xining with water production moduluses being 284,000 and 229,000 cubic meters per square kilometer respectively. The two counties Huangzhong and Huangyuan as well as the Xining downtown, with water production moduluses being 175,600, 107,800 and 109,700 cubic meters per square kilometer respectively, are resource-oriented areas with serious shortage of water.
Second, uneven spatial and temporal distribution of water resources, making it difficult to utilize the water resources. The water resources of Xining mainly come from precipitation. The water vapor in the fishbone-shaped valleys of Xining forms special characteristics of precipitation, presented with three high value zones and one low zone . The zone with the highest precipitation of the three high value zones is located in the south foothill of Daban Mountain at an elevation of 4300 meters and with annual precipitation of 801.8 mm. The zone with low precipitation is located at the south section of Huangshui River Valley at an elevation of 2168 meters and with annual precipitation of 339.7 mother distribution of precipitation in a year is extremely uneven with that from June-September accounting for above 70% of the annual precipitation and that from November of this year to May of the next year accounting for 30% of the annual precipitation. The amount of water resources of Xining is recharged by precipitation. Affected by seasonal precipitation, the annual and interannual amounts of water resources change obviously. The amount of runoff from June-September during flood season accounts for 63% of the amount of surface water resources whereas that from November of this year to May of the next year accounts for only 37%.The interannual variation of water resources synchronizes with the interannual precipitation but with relatively larger amplitude of variation The areas with abundant underground water in Xining only includes Shijiazhuang and Ta'er area of Datong county in the valley plain, and Danma Temple, Duoba and Dujiazhuang of Huangzhong county. The exploitation amount of underground water accounts for above 60% of that of Xining city. The uneven spatial and temporal
of water for industrial and agricultural production and living of urban residents as well as difficulties in exploitation and utilization of water resources. Engineering water shortage and resource-oriented water shortage coexist.
Third, pollution of water bodies aggravates, resulting in reduced amount of available water resources. With rapid economic and social development of the city, discharge of wastewater is increasing day by day, resulting in aggravated pollution of water bodies. Among the 17 water quality monitoring points for monitoring sections of Huangshui River Basin, the water quality of 9 of them is better than and just reach the standard of water of class III and the water quality of 8 of them is poorer than the standard of water of class III. The substances causing the pollution mainly include five-day biochemical oxygen demand, ammonia nitrogen and total phosphorus. The water functional zones of Xining that are seriously polluted include Xining industrial water consumption area and Xining sightseeing and entertainment water consumption area of Nanchuan. The functional zones of Huangshui River trunk stream and Beichuan are also seriously polluted after entering the Xining urban area.
Pollution of water bodies has restricted the utilization of comprehensive benefits from limited water resources, destroyed the ecological environment of Xining and worse still caused water shortage due to poor quality of water in middle and lower reaches of Huangshui River.
4.1.2 Current Situation of Water Resources Development and Utilization
Water supply: The annual amount of water supplied by various water conservancy projects of the city in 2012 was 675 million cubic meters accounting for 51.4% of the total amount of water resources of the city. The amount of water supplied by surface water conservancy projects was 337 million cubic meters accounting for 49.9% of the total water supply and the amount of water supplied by underground water conservancy projects was 338 million cubic meters accounting for 50.1% of the total water supply.
Water use: The total water use of all national economy sectors of the city in 2012 was 675 million cubic meters, among which the water use for living of residents in urban and rural areas was 131 million (accounting for 19.4%), industrial water use was 208 million cubic meters (accounting for 30.8%), water use in ecological environment of urban area was 12 million cubic meters (accounting for 1.8%), water use in farmland irrigation was 265 million cubic meters (accounting for 39.2%) and water use in forestry, animal husbandry and fishery was 59 million cubic meters (accounting for 8.8%). The total water use of the city accounts for 51.4% of the total amount of water resources of the city.
4.1.3 Prediction of Water Supply and Demand
In 2005 (i.e. early stage of the 11th five-year plan), water use of national economy sectors in Xining Municipality was 590 million m3. However, with seven years of rapid economic development, the water use in 2012 reached 675 million m3, an increase by 85 million m3 or an average increase rate of 2.0% per year.
As per 12th Five-year Plan Outline for National Economy and Social Development of Xining Municipality, by 2015, gross value of production will be more than two times of that at the end of 11th five-year plan, and the gross value of production is expected to reach RMB 132 billion. It is predicted that the gross value of production of primary industry will increase by 5% (expected to reach RMB 2.8 billion), the gross value of production of secondary industry will increase by 16% (expected to reach.
RMB 73 billion with industrial growth of 17% (expected to reach RMB 65 billion), and the gross value of production of tertiary industry will increase by 13% (expected to
reach RMB 56.2 billion).
As per development planning of industries and national economy sectors, it is predicted that total water demand of Xining Municipality will reach 850 million m3 by 2015 (when P=75% in relatively dry hydrological year), and by 2020, total water demand of Xining Municipality will reach 1.05 billion m3. If no additional water supply works is added, by 2015, water shortage will be 150 million m3 and 350 million m3 by 2020. The water resources which can be developed in Xining Municipality are seriously insufficient, and the restriction of water resources on economic development in Xining Municipality becomes more serious.
4.1.4 Alternative Sources for Water Resources
Many water sources are used for urban miscellaneous water purposes, currently being tap water, surface water, groundwater and reclaimed water.
Based on comparison of multiple water resources (Table 4.1-1), reclaimed water is finally selected to be used as water source for miscellaneous water in Beichuan area.
Table 4.1-1 Table for Comparison of Alternative Water Sources for Urban Miscellaneous Water Uses
Supply Usage Cost Urban Planning and
Development Layout Feasibility Advantages and
Disadvantages
Tap water
The current urban water supply is close to scale of water supplied longer to be used as water source for industrial water uses, and to be gradually stopped from being used as water source for greening
No surplus amount exists, thus not feasible to be used as water source worldwidely accepted safety limit of 40%
Class-IV
It is too expensive to construct new headwork and long-distance water diversion and distribution pipes banned already. With falling of underground water level, the existing wells cannot effectively supply water any more
Constrained abstraction, difficult well construction in some areas, hard water
Reclaimed
Water quality of treated waste water in Xining is good with
See table 4.1-2 for the proposed alternative water source of reclaimed water to be supported under this project.
Table 4.1-2 Proposed Reuse of Reclaimed Water as Alternatives Water Source
Water Users Water Source Alternative Water Source
For green space irrigation and road watering in core area of Beichuan
The area is still a planned development area, not yet established. However, for greening water uses, tap water is currently the main water source in Xining.
Discharge from the reclaimed water plant in No.5 WWTP