Wang Kai-zhang¹, Li Bin¹, Yu Quan-fa², Wang Jin-jin¹

1 Shandong Agricultural University, Tai’an, 271018, China;

2 Shandong Water Polytechnic, Rizhao, 276826, China )

 

Abstract: Water is not only the origin of life, but also irreplaceable natural and strategic resource for sustainable development of human society and it is indispensable part of comprehensive national strength. The sustainable utilized water resource and the beneficial cycle of it are crucial factors that influence the regional economic development and the civilization of society. In Shandong Province Peninsula, groundwater is the fundamental resource that supports economic development. With the fast development of economy, the phenomenon of water shortage and water environmental deterioration is more and more serious. Therefore, constructing underground reservoir is an important approach to solve contradictions, to optimize collocation of water resource and to actualize sustainable development. Through the achievements of underground reservoir constructions in Shandong Province Peninsula, this paper expatiates on the type and technological measures of underground reservoir. Moreover, it discusses the beneficial effect of constructing underground reservoir in this area and points out that with the help of underground reservoir the steps to regional sustainable development will be accelerated. In the end, this paper provides scientific gist for harmonious development of economy, society, energy and environment in this area.

Key Words: underground reservoir; beneficial effect; sustainable development

Population, resources, environment are major issues that humanity face today. On the coast, the ecological environment is particularly fragile, highly vulnerable to man-made factors and destruction. The problem is seriously restricting the economic and social development and the improvement of people's living conditions on the coast. Groundwater is the main sources of water of industrial and agricultural production ofShandong Province Peninsula, urban construction and living water, it is accounting for more than half of all the total water volume. With the rapid economic development, water shortages and water deterioration of the environment have become increasingly prominent. Building underground water reservoir becomes an optimization of the allocation

1 The Survey of Water Resources in the District

Shandong Province Peninsula is located between the Huanghai Sea and Bohai Sea. Its terrestrial coastline is 2930km, and the offshore islands are about 240. Including Qingdao, Yantai, Weihai, Weifang, Zibo,Rizhao, Dongying, its total area is 65,100 km² and the total population is 33.18 million. For many years, the average temperature of the district is 12-13 Celsius degrees; the rainfall is 650-910mm. In addition to theYellow River surface water, there are marginal water into the sea. In Shandong Province Peninsula, the years’ average total water is 10.317 billion m³, per capita water volume 311m³/, only 1/6 of the national average, lower than the bottom-line of the per capita possession of water resources  (1000m³/) according to World Bank Development Report. In recent years, Shandong Province Peninsula has become the front of  the CentralBohai Sea economic zone of the country and the rapid urbanization of the country when the high-speed economic growth occurs. The shortage of water resources has weakened its ability to support sustainable economic development and posed a serious threat to its economic base ^[1].

Groundwater is the main sources of water of industrial and agricultural production, urban construction and living water in the district. The 1994-2003 decade, seven prefectures' water supply and the average proportion of the volume of water by groundwater are shown in table 1.  With the exception of Dongying, whose water supply depends on Yellow River, in Qingdao, Yantai, Weifang and Zibo the 4 prefectures' water supply mainly relies on groundwater; in Weihai and Rizhao there is also 1/3 of the water supply from the groundwater. So the need of water requirement increases, so the cultivation and the utilization of the water resources go further year by year.

Table 1.  Seven prefectures' water supply and the average proportion of the volume of water by groundwater        Unit: 10⁸m³

	Qingdao	Yantai	Weihai	Dongying	Weifang	Zibo	Rizhao
The volume of water supply The volume of water by groundwater The average proportion	11.0388     5.6384     51.08%	12.2373     7.6153     62.23%	3.6699     1.3543     36.90%	11.8324     1.0035     8.48%	20.0028     13.3331     66.66%	13.4252     9.9448     74.08%	5.6881     1.8353     32.27%

This area is one of the areas short of water resources in China; the lack of water is especially serious in the city. The project of guiding water from the Yellow River, the east line of the South to North project of theYellow River and West to East water project ^[2] still could not satisfy the water supply demand which grows day by day. From the view of ecological development , the recent years’ economic development, the abuse of water resources and  the ignorance of water preserve have caused a series of interaction effects^[3,4] on the geological environment, water environment and ecological environment, which resulted in the serious destruction to the ecological environment of this area. And the water environment condition tends to deteriorate, such as the expanding over-exploited funnel , the sea (salty)-water invasion, underground water pollution , and ect.

Facing the shortage of water resources and the deterioration of water environment, it is not wise to constantly enlarge the water resources mining quantity or purely rely on drawing water from long distance .According to the peninsula urban cluster ecosystem it must implement the sustainable water supply engineering construction as circumstances permit. In the Shandong Peninsula area, the rainfall is centralized, the rivers fast. In the flood season  the surface runoff abandons released into the sea are so massive that makes the lack of the water  into a sharp contrast. Therefore, the construction of the underground reservoir, to guide the surface water go underground, to store and regulate the implementation water resources underground, to alleviate the shortage of water resources, and to build a benign circle of the economy, the society, the resources and the environment, is the cores of the water resources’ sustainable use in this area^[5].

2 Underground Reservoir Types and Related Technologies of this Area

2.1 Underground reservoir types

In accordance with the area’s general configuration of the earth’s surface and hydrology and engineering facilities of underground reservoir, Shandong Province Peninsula’s underground reservoir can beclassificated as Dam Type 、None-Dam Type and Funnel Filling Type；In accordance with the geology , general configuration of the earth’s surface and hydrology of underground reservoir, the area’s underground reservoir can be classificated as Intermotane Valley Type, Littoral Plain Type, Alluvial Fan Type and Alluvial Plain Old River Course Type.

In the west of Peninsula, the alluvial river terrain is relatively flat; aquifer is thick and widely distributed, the undergroundwater runoff conditions are poor and the level-directed runoff is not in the major status. So, such areas are suitable to build None-Dam Type Underground Reservoir. Huantai underground reservoir is a good example.

In the east of Peninsula, in the middle and lower reaches of the river, the aquifer of river   alluviation is good in infiltration performance , the grade surface high and the runoff conditions good, and the specially good is the aquifer extended in a strip. Both sides are almost impermeable stratum, more suitable for building Dam Type underground reservoir,  Longkou Bali River underground reservoir has rich experiences.

Underground water overexploited funnel is the drainage spaces because of long and massive exploitation, in fact , it is almost a complete closure underground Reservoir. In use of water-rich period and other period for second time irrigation and provision technology, to resume the dynamic equilibrium of groundwater soon is called Funnel Filling Type. This kind of underground reservoir is in planning and construction in Shandongand China.

2.2 Related engineering technology in use

Underground reservoir engineering systems is made up of Second time irrigation and provision project、Water storage retarding project、Ground Curtain-dam project、Discharge project、Drawing-water project, Supplying water project and Management monitoring project. Second time irrigation and permeating provision technology、High pressure grouting screen impervion technology and Numerical simulation technology are all in scientific use in this area for underground reservoir construction, and they have made good effects.

2.2.1 Second time irrigation and permeating recharge technology

The key of the underground reservoir’s construction is how to choose the providing headwaters of the underground reservoir (water quantity and water quality) and the technology of second time irrigation and permeating. In view of hydrogeology, in the area where surface water has inseparable connection with underground water, the excitation recharge because of exploiting underground water will enlarge the permeating recharge from surface water to underground water, which makes the guiding provision when the underground water table is lower than the surface water level , and the providing quantity has connection with the osmosis of the water-bearing stratum and the distance between source of water and surface water. Due to the big drop of underground water table in the place of building underground reservoir in Shandong Peninsula District, it is a good idea to use the method of pouring water into underground to make second time irrigation and permeating recharge. Many permeating provision technologies have been successfully used on the basis of the hydrogeology conditions when the underground reservoirs were built .For example: intercepting surface water by steps ,combining negative wells with driven wells, and combining percolating basen with percolating pit( the infiltration gallery or permeable channel)from surface water into underground water ,or other manmade quick permeating technologies. At the same time, in order to ensure the water quality of the source which is used for second time irrigation, separating effluent from flood and draining away the effluent into oceans intently by ducting.

2.2.2 Impervious technology

Due to the geological conditions, most of the underground reservoirs require impervious address, so impervious technology is the focus of building underground reservoirs technical measures for construction techniques and has high quality requirements. For impervious governance, a great deal of discussion and practice has been done at home and abroad, focus on finding the suitable measures to local conditions for the different geological condition and the result of leakage. Impervious technology includes grouting screen and impervious wall for their different structure.

The high pressure jet grouting technology of grouting screen is suitable for most stratum and the new building underground reservoirs, but the price of the technology is a little high. The Wang River underground reservoirs adopt the underground impervious wall which is 1.36×10⁴meters costing 1.5×10⁸ Yuan. The major portion of the building is built based on the high pressure jet grouting technology . For another, Longkou BaliRiver, Longkou Huangshui River, Yantai Jia River also build underground impervious wall in their underground reservoirs based on the same technology. The chemical grouting screen has a lot of advantages .For example: the technology is handy and nimble, holding little place when it is working, influencing less on the around environmen.But there are no according regulates, quality control standard or detailed supervising rules^[6]. In view of requirements from the underground reservoir construction, concrete impervious wall is one of the most effective measures for overburdens’ impervious technology at the toe of the dam, because it can be widely applied to various geological conditions, with technical reliability and economic advantages . Concrete high pressure jet technology is used when the underground reservoir of Qingdao Dagu River was being built. The impervious wall that covered 3.16×10⁴ m² assures the largest capacity of reservoir 3.84×10⁸ m³.The impervious wall not only stops the underground undercurrent running into sea , but also stops the seawater running into the underground reservoirs.

2.2.3 Numerical simulation technology

In underground reservoir management planning, second time irrigation and provision project and the underground reservoirs ‘monitoring can be numerically simulated by using modern numerical simulation technology, which supplies foundations for making suitable plan of providing project’s management ,control and lash-up project of underground reservoirs. For example, Huangshui River underground reservoir uses numerical stimulation to establish “Four-dried-one-plentiful season”dispatched run managing model and the emergency counter plan of fighting a drought, which makes the artificial recharge quantity of underground reservoir reach 22 million m³ in plentiful water year, also increase 3 million m³ in draught year, assuring groundwater level not to drop to a big degree^[7].

 

3 The Analysis of Beneficial Resource and Environment Effect in Underground Reservoir Construction

3.1 The analysis of macro-scope effect

Shandong Peninsula underground reservoir research and construction have scored some achievements so far. Since the 1990’s, Longkou Bali River, Longkou Huangshui River, Qingdao Dagu River, Yantai JiaRiver and Laizhou Wang River have been built in large, medium-sized underground reservoirs successively.,as shown in Table 2.

Table 2  The statistics tables of the underground reservoirs built

Underground Reservoir Name	Aquifer Lithology	Reservoir Area（km2）	Aquifer Thickness（m）	Drainage Area（km2）	Underground Dam Length（m）	Storage（104m2）	Built Time
Longkou BaliRiver LongkouHuangshuiRiver QingdaoDagu River Yantai JiaRiver LaizhouWang River	Gravelly Stone Sandy Grit   Gravelly Stone Grit Scree Grit Stone	14.7   51.82     421.7   65   68.49	4-6   2-5     5-19   5-30   6-36	47.75   1034     4631   2296   326.8	756   5996     2600   3890   13500	42.97   5359     38400   20500   5693	1990   1995     1998   2000   2004

These built underground reservoirs have left a significant influence in easing the contradict of the local supply and demand of water and in improving the ecological quality of the environment, mainly in the following three aspects:

(1) Supplying water, reducing water mining cost and easing the contradictions in the supply and demand. Five underground reservoirs can vacate storage nearly 700 million m³, will produce more than 10 billion economic benefits and ease contradictions of four cities in the supply and demand of water resources, particularly the implementation of the water resources underground modulation can resolve water resources uneven time distribution in the region and make sustainable use of water resources, while make underground water level rise, not only reducing  the costs of water harvesting, but also bringing good environmental benefits.

(2) Reducing the flood and drought disaster. Shandong Peninsula’s rainfall is centralized, the yearly changes large, and the flood and drought disaster occurs frequently. In spatial pattern, five underground reservoirs all are close to rivers, all having close water power relation. The completions of underground reservoir cause water-control to effectively unify with the water utilization. Through storing the flood season water in the underground reservoir, the disasters inlocal and downriver are reduced, on the other hand , the local water sources are supplemented. It also may coordinate the contradictory of upriver and downriver the water used, melting harms for the advantage.

(3)Improving the ecological environment. From the perspective of the region ecological environment, five built underground reservoirs can avoid the excessive exploitation of surface water and reduce deterioration of the ecological environment caused by the shortage of surface water; Allow river to maintain a certain amount of water used in ecology, conducive to river protection and restoration of ecosystems. Through storing conserved water, the water resources can increase humidity, regulate climate, purify the air and reduce sandstorm, also can significantly improve small climate in part region and promote local ecosystems to a benign circle. On the other hand, since the establishment of the underground reservoir, the water structure could be adjusted to the underground reservoir for drinking high quality water, surface water for agriculture and so on, implement supplying water according to the quality, the better quality the better use and synthesized use.

3.2 The analysis of microcosmic effect

The following is to take the Qingdao Dagu River and Laizhou Wang River underground reservoirs as examples to analyze the microcosmic effect of the underground water reservoirs in easing water resources tensions and improving ecological environment.

3.2.1 Dagu river underground reservoir

Qingdao Prefecture begins to build Daigu River underground reservoir in 1998. Daigu River underground reservoir located on Daigu River valley downstream plains along the ancient river distribution, its north toLaizhou Prefecture Sunshou Town Jiangjia Villaye Barrage and Pingdu  Prefecture Guxian Town Longhu Hill Barrage, south to Jiaozhou Prefecture Jiaodong Town Damawan Village. The reservoir area is 421.7 km², the north-south length 51km, the average width 8km ,and the Daigu River underground reservoir enhances the utilization rate of Dagu River water through downstream underground impervious wall, midstream seven barrage and Laixi sewage treatment and a series of measures.

The underground reservoir of Dagu River is completed, increasing the upstream deposited water quantity by impervious wall interception underground storage capacity, while preventing invasion of sea water to upstream impervious wall. Results of monitoring impervious wall upstream underground water in 1999-2001 years indicate that the present content of chlorine particles is on the overall downward trend and other chemical elements are on the decrease year by year, as shown in Table 3.

Table 3   the comparison of out-standard particles after the reservoir was built

After "Taozhi" typhoon and the following rainstorm in August 2001, around the reservoir area the underground water level rose by an average of 2.05m, increasing the quantity of the water 86 million m³, intercepting the surface water effectively, conserving the ground water sources, improving water supply capacity, offers water resources safeguard to the economic development of Qingdao Prefecture.

3.2.2 Wang river underground reservoir

The Wang River underground reservoir which jointed venture with Japanese OECF^[8], was constructed in Guoxi Town, Xili Town and Pinglidian Town in Laizhou Prefecture in December 1999, and was run in August 2004. The reservoir’s permeate provide quantity is about 32×10⁶ m³, the total area is 68.49 km², the total capacity of reservoir is 56.93×10⁶ m³, and maximum regulating capacity of reservoir is 32.73×10⁶ m³. Those produce the remarkable integrate benefit, in economy, society and ecology, mostly embodying:

(1) Reducing sea-water invaded area. The maximum of underground  water level raised is 4.44m higher after constructing groundwater reservoir than before constructing groundwater reservoir, and the average level is 3.31m, (Reference Fig.1); Because of groundwater level’s rise, the sea-water invaded area reduce from 78.69 km² to 25.36 km², by 68%.

Fig.1 Changeable undergroundwater level map of fore-and –aft building reservoir

(2) Improving the water quality, and increasing the capability of water supply. After constructing underground reservoir, the chlorine at least is reduced by 71.1%; with the average decrease 50.6%, (Reference Fig.2),which thoroughly resolved the difficulty of people and livestock’s drinking, and ensured the supply in big industrial factories. Meanwhile, new water supply fields are opened up of, establishing 15×10³t water supply for each factory.

Fig.2 Changeable Chlorine particle content map of fore-and –aft building reservoir

(3) Enhancing ecological function and avoiding natural disaster. Overabundant water( 32.73×10⁶m³ )from rainfall and runoff is deposited by underground reservoir; with the help of the regulating dam, the resume of 334 hm² marsh comes true step by step, and the flood-drought disaster caused by the varied rainfall in a particular year or  years can also be avoided.

(4) Raising production capability and stabilizing public order. After eliminating the  sea-water invasion, this area resumes and ameliorates ecological environment, improves industrial and agricultural production capability, as the result, it increases provisions 10×10³ t per year, with the economy benefit about 30×10⁶ yuan, and greatly relives local residents’ troubles.

The construction of Wang River underground reservoir provides the mighty support of water resources and ecological environment to the economic and social sustainable development of Wang River river’smiddle-lower reaches. Water regulating and storing in underground reservoir gains the double bumper harvests of economic, social and ecological environmental benefit,whose successful practice is worth learning and applying.

3.3 Prediction

According to the constructive condition (water-rich area distributing, the feasibility of exploiture utilizing and economic conditions) the integrated analysis believes that, there could construct about 50 big and middle-sized underground reservoirs in Shandong Province Peninsula, among which, there are 12 underground reservoirs in Qingdao Prefecture, 20 in Yantai Prefecture, 6 in Weihai Prefecture, 2 in Rizhao Prefecture, 12 in Weifang Prefecture, 2 in Zibo Prefecture, and mostly distributing along the coastal areas of peninsula, piedmont alluvial plain and Jiaolai basin. We forecast that the underground reservoirs’ total regulated water quantity is 3.9 billion m³/a, and will increase the total groundwater storage regulated exploitation by 1.5 billion m³/a. There are 13 feasible constructed underground reservoirs whose maximum regulate storage is above 10×10⁶m^3[9],(the statistics as Table 4 and sketch map as Fig.3 ).

Table4 Statistics of Some Feasible Constructed Underground Reservoirs

There will produce remarkable economic, social, resources’ and environmental integrate benefit to Shandong Province Peninsula after the over 50 underground reservoirs have been constructed. With survey and calculating, the increased total groundwater storage regulated exploitation can produce the economic benefit of about 3.6 billion yuan, (The different industrial distribute structure of water utilization in Shandong ProvincePeninsula is

agriculture 64.4%, industry 22.9%, living 12.6% ) . According to the target of water used in ecology (0.62% ) in 2003 in Shandong Province, we can calculate that the water used in ecology increased by 1 million m³/a, will prodigiously improve ecological environment althrough Shandong Province Peninsula; meanwhile, the overexploited funnel area and sea-water invaded area will reduce further (Fig.4), so it will establish a basic condition for improving the regional ecological environment quality.

Built Underground Reservoir ⑧ Feasible Constructed Code and Position

Fig.3 Location map of underground reservoir area

Fig.4 Changeable overexploited funnel and sea-water invasion map of after building underground reservoir

4 Conclusion

Shandong Province Peninsula District’s construction of the underground reservoir according to the local conditions, to some degree, has eased the contradictions of supply and demand of water resource. The achievements on the underground regulating and storing and joint controlling of water resource can ensure the sustainable use of the water, so as to support and guarantee the sustainable development of this area.

Underground reservoir construction has made double benefits in resource and environment of Shandong Province Peninsula, not only easing the lack of water resource , but also improving the quality of ecology. A virtuous resource and environmental circle will format if underground reservoir is completed, and it will help the socio-economic sustainable development a lot.

Underground reservoir construction is an as independently as interrelated systematical engineering, which is impacted by general configuration of the earth’s surface and hydrology、engineering technology、quality of ecological environment and socio-economic conditions. Underground reservoir also needs perfect monitoring system 、remote control system and data collection system,. Shandong Province Peninsula District has some good experience in underground reservoir construction, but some further researches still should be done in operation and management of underground reservoir as well as in the underground water’s vunerability and manmade rapid permeating, ect.

 

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