The Status and Disaster Losses of Seawater Intrusion in Kiaochow

Bay Region

Jianwei

ZHANG

1,2,3

, Shuya HU

and Zhongcheng LU

Department of Environmental Sciences, Qingdao University, Qingdao 266071, China

School of Ocean Sciences, China University of Geosciences (Beijing), Beijing 100083, China

Geo-Engineering Investigation Institute of Qingdao, Qingdao 266100, China

{f_author, t_author} dragonzjw@126.com

Keywords: Seawater Intrusion, The Status, Disaster Losses, Kiaochow Bay Region.

Abstract: By analyzing the history about seawater intrusion of the Dagu river estuary, Baisha river estuary, Yang river

estuary and Xin’an region, we study the seawater intrusion in Kiaochow Bay region. With the content of Cl

200mg/L, 250mg/L, 300mg/L in groundwater as main index, we divide Kiaochow Bay region into four

parts: non-seawater intrusion region, the slight one, the more serious one and the severe one. And we can

conclude that the most serious seawater intrusion region is the river estuary, it will be gradually less serious

in backland and two banks of rivers. We estimate the direct economic of the seawater intrusion region.

1 INTRODUCTION

Human long-term remaking nature and developing

economy, destroyed the natural environment of

relative balance(

Cao B X, 1995

). Excessive

exploitation of water resources makes the situation

of the water resources and ecological environment is

becoming more and more serious. Almost all coastal

areas are densely populated areas. A large amount of

water demand has caused great pressure on

groundwater resources, and excessive exploitation of

groundwater has become more serious. In Europe,

there are at least 100 areas affected by seawater

intrusion effect(

Scheidleger A, 2004

); such as the

Netherlands, have the enough fresh water resources

from the river and the atmosphere, but more than 20

wells forced to close by the action of seawater

intrusion in the past few decades(

Freedman V and

Ibaraki M, 2002; Stuyfzand P J et al, 2004

Kiaochow Bay is the mother Gulf of Qingdao, is

located in the south of Shandong Peninsula, also

known as the Jiaoao. There are the Nanjiao River,

Dagu River and other rivers flow into the Kiaochow

Bay. The seawater intrusion of Kiaochow Bay

region originated in the 1970ˊs, which has been

developed for several decades, and the scale of

invasion has been increasing(

Luan X M et al, 2009

2 DEFINITION OF SEAWATER

INTRUSION

Xue Yuqun gives the definition of seawater intrusion

from the perspective of its mechanism and

evolution(

Xue Y Q et al, 1992

): if the groundwater

was pumped more than recharged it, when the

groundwater head of the coastal zone decreases to

below the head of the sea water, the interface

between salt water and fresh water is going to be

pushed to the land until a new balance is formed,

that is the seawater intrusion. Wang Bingchen gives

the definition of seawater intrusion from the angle of

influence(

Wang B C, 1995

): seawater intrusion is a

natural phenomenon due to the decline of the

groundwater level in land caused seawater intruding

to the aquifer in the coastal areas. Jiang Jiali

analysed seawater intrusion from the angle of

inducement(

Jiang J L, 2002

): in the coastal areas, over

exploitation of groundwater leads to groundwater

depth decline, then the dynamic balance of salt water

and fresh water was destroyed, that the groundwater

is directly invaded by the sea water.

HU S., LU Z. and Zhang J.

The Status and Disaster Losses of Seawater Intrusion in Kiaochow Bay Region.

DOI: 10.5220/0006018300150019

In Proceedings of the Information Science and Management Engineering III (ISME 2015), pages 15-19

ISBN: 978-989-758-163-2

3 RESEARCH AREAS AND

METHODS

3.1 Research Area

Shandong province and Qingdao city carried out the

strategy of protection and development surrounding

the Kiaochow Bay Region. Within all variety of

geological hazards which exist in Kiaochow Bay

region, seawater intrusion is of the largest scale, the

most influential and the most serious hazard losses.

Therefore, study area includes the West of Shinan

District, the old port area, the West of Sifang

District, Hongdao area, Shaohai of Jiaozhou city,

Huangdao eastern regional area, that the total area is

about 500km

3.2 Research Methods

We get the newest seawater intrusion data of the

content of Cl

and other chemical composition in

groundwater, which corresponds to a hydrological

year’s. With the different content of Cl

as main

standard of the seawater intrusion degree, we

divided Kiaochow Bay region into serious parts. We

evaluated the disaster loss of seawater intrusion by

the mathematical methods.

4 TYPICAL SEAWATER

INTRUSION AREA

The seawater intrusion of Kiaochow Bay coastal

areas began in the 1970's, and the start time and the

process of development are different in the different

shore section, the interannual change and the

influence factors are different also, and take

prevention measures of seawater intrusion also

varies. Typical seawater intrusion area includes four

shore section of Dagu River downstream, Baisha

River downstream, Yang River downstream and

Huangdao Xinˊan area.

4.1 Downstream of the Dagu River

In the downstream area of Dagu river has large

distribution of salt water. Its marine silt sediment

layer has been extended to Lancun of Jimo North.

Since 1981 developed the groundwater of Dagu

River downstream to supply the Qingdao city,

Ligezhuang area has formed groundwater drawdown

funnel about 100km

, and the lowest groundwater

level -8.18m in the center, caused seawater intrusion

gradually in the southern and southeastern. At the

same time, because the poor management of

Nanzhuang Dongfeng gate in the downstream of the

Dagu River, resulting the seawater traced back to

Hejiazhuang village, and distance estuary up to

12km. Because of groundwater level is lower,

seawater intrusion is very favorable, resulting in

groundwater quality deteriorated significantly along

both banks of the river, compared to 1988 and 1981,

the front of seawater intrusion carried about 750m,

the effect area is 3km

. After 1990, with the water

conveyance project from the Yellow River to

Qingdao city, the amount of groundwater

exploitation reduced, and precipitation increased

than the 1980s, the high water period of funnel does

not occur again after 1994. In 1997, the engineering

of underground seepage prevention curtain wall has

constructed in Xiaomawan, salt water not to expand.

overall, the Cl

concentration and salinity have

downward trend. During the extremely dry years of

2002, downstream of the Dagu River seawater

intrusion area did not change much due to take

measures in advance. After 2004 and 2005 years, the

groundwater has supplied, seawater intrusion trend

slowed down significantly, groundwater quality has

the signs of recovery. But near the Ligezhuang area

of seawater intrusion, the exploitation area of

groundwater is mining, the water supply capacity is

reducing, so that residents using water is difficult.

4.2 Downstream of the Baisha River

Baisha downstream is the groundwater source area

near Qingdao city. Its aquifer is the alluvium and

diluvium of the Baisha River, and has excellent

quality water in the 1960s. In the 1970s,

groundwater overexploitation, underground water

level gradually decreased, that caused seawater

intrusion. In 1984, it has formed groundwater

drawdown funnel about 25km

, and the lowest

groundwater level -9m in the center. So it became

the earliest and most harmful area of seawater

intrusion in Qingdao city. In the middle of the

1980's, the seawater intrusion area reached 8.5km

Until 1985, under the influence of the ninth

Typhoon, the seawater intrusion has eased, and then

continued to develop slowly. It is the abundance of

groundwater in 1990, the groundwater funnel were

pacified, and groundwater exploitation amount is

reduced, to compensate the groundwater, seawater

intrusion area stepped back a little. It is extremely

dry year in 2002, seawater intrusion increased, some

villages disaster is very serious, such as Qianhaixi

village is completely surrounded by salt water, near

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the little water can be drunk. As the vegetable

planting base of Qingdao, seawater intrusion caused

vegetable cannot grow, that yield 70%, grain also

significantly cuts or even, a large number of wells

scrapped.

4.3 Downstream of the Yanghe River

The groundwater exploitation in downstream of the

Yanghe River based on agricultural water supply,

and the area is five small river estuary (also known

as the "five river estuary "). Seawater along the river

upstream, caused seawater intrusion, the intrusion

area has occurred large area of grain production and

wells scrapped phenomenon.

4.4 Downstream of the Xin’an River

Seawayer intrusion area is located in Xin’anhe River

downstream estuary, and the distance to the coast

nearest less than 500m. Because of the mining

amount greatly exceeds the natural recharge in the

1980s, the water level drops quickly, the lowest

water level elevation is -3m, leads to seawater

intrusion. Since the beginning of 1986, the distances

of seawater intrusion is 600m or so. The amount of

the mining is reduced gradually until the total is

stopped.in 1986 ~1995 years, At present, there are

some phenomena such as land salinization, farmland

damage, rural water use difficult and so on. Now

surface water is the main supply source, the trend of

the intrusion of sea water has been contained.

5 DISTRIBUTION

CHARACTERISTICS OF

SEAWATER INTRUSION

5.1 Status Survey

Seawater intrusion is affected by human factors, is

due to the over exploitation of groundwater,

saltwater and freshwater interface changed, seawater

intrusion into freshwater aquifers, form the disaster.

So the range and distribution of seawater intrusion is

in constant change. Through the investigation of the

current situation of the seawater intrusion in a

hydrological year, we can get the latest data of

intrusion.

A total of 544 groundwater samples were

collected. In the sample collection process, we also

investigate the water intake point information, such

as the landscape, environment, mining methods and

others.

Samples were collected by successive encryption

sampling method, a total of three times. First, 220

groundwater samples were collected in the region,

according to the results of laboratory tests to

understand the overall situation of water quality.

Then according to the distribution of Cl

content, in

the distribution of the 200mg/L, 250mg/L and

300mg/L boundary lines are encrypted 200 samples.

Finally, according to the results of the previous two

analysis, we selected the key and the typical section

to collect 124 samples. So there are two purposes.

One is to fill some of the sampling area by the

supplementary sampling in the study area. Two is a

better analysis of the characteristics about the

current situation of seawater intrusion through the

targeted encryption.

5.2 Status Characteristics

According to the results of Cl

, we used the Excel

software and Surfer software to generate the

equivalent line automatically. Isoline map and

MapGIS map were corrected, and the Cl

content

said in a location map.

With the content of Cl

200mg/L 250mg/L

300mg/L in groundwater as main index we divide

Kiaochow Bay region into four parts: non-seawater

intrusion region, the slight one, the more serious one

and the severe one. And we can conclude that the

most serious seawater intrusion region is the river

estuary of Dagu river, Baisha river and Yang river

and Xin’an region of Huang island, it will be

gradually less serious in backland and two banks of

rivers.

5.3 Seawater Intrusion Area

The invasion area was low, the ground elevation is

generally less than 10m. The formation is the

Quaternary sedimentary layer. According to the

different geographical position, from the coastline to

the Cl

concentration of 250mg/L, we can get the

area ratio of the affected area of the seawater

intrusion.

Dagu River downstream region of seawater

intrusion affected area is the largest, accounting for

main intrusion zone 46%. Followed by Baisha

downstream, the Yanghe River downstream area,

and the area of seawater intrusion in Huangdao area

is the smallest, which accounts for 9% of the main

invasion area. The area of seawater intrusion is

The Status and Disaster Losses of Seawater Intrusion in Kiaochow Bay Region

related to the regional hydrogeology, groundwater

utilization and exploitation.

Figure 1: Distribution of seawater intrusion area in the

Kiaochow Bay region.

Downstream of the

Baisha River

27%

Downstream of the

Yanghe River

18%

Downstream of the

Xin’an River

Downstream of the

Dagu River

46%

Figure 2: Percentage of major seawater intrusion area.

6 LOSS OF SEAWATER

INTRUSION DISASTER

The seawater intrusion is a geological disaster of

slow degeneration, which has a wide distribution

area, which is often not easy to cause people's

attention, but the economic loss caused by it is huge

(

Li P et al, 2004

). The seawater intrusion area of

Kiaochow Bay is mainly in the farmland and

vegetable planting area, the seawater intrusion has

destroyed the underground fresh water resources,

which has brought the extremely disadvantageous

influence to the agricultural production. Due to

differences in lots of different soil texture and

cultivated species, it is difficult to accurately

calculate the seawater intrusion disaster loss. But

according to the value of agricultural production

caused by seawater intrusion, agricultural production

was more than 15% in the concentration of Cl

250mg/L~300mg/L area, and agricultural production

was more than 35% in the concentration of Cl

higher than 300mg/L area.

In the Kiaochow Bay region, the concentration

of Cl

at 250mg/L~300mg/L area is 114.5km

, and

the concentration of Cl

higher than 300mg/L area is

73.5km

. The normal agricultural output of

Kiaochow Bay coastal areas is 4.5 million yuan/km

Then in the area of the concentration Cl

250mg/L~300mg/L, agricultural production loss:

114.5km

× 4.5 million yuan/km

×15%=77.29

million yuan

And in the area of the concentration Cl

higher

than 300mg/L, agricultural production loss:

73.5km

× 4.5 million yuan/km

× 35%=115.76

million yuan

The sum of these two is the total disaster loss,

that is to estimate the direct economic losses caused

by seawater intrusion in the Kiaochow Bay region

every year, about 193.05 million yuan.

7 CONCLUSIONS

With the content of Cl

200mg/L 250mg/L

300mg/L in groundwater as main index, we divide

Kiaochow Bay region into four parts: non-seawater

intrusion region, the slight one, the more serious one

and the severe one. And we can conclude that the

most serious seawater intrusion region is the river

estuary, it will be gradually less serious in backland

and two banks of rivers.

We have evaluated the economic damage caused

by the seawater intrusion in the Kiaochow Bay

region, which is 193.05 million yuan every year.

ACKNOWLEDGEMENTS

The study is financially supported by the National

Natural Science Foundation of China (No.

41202175).

ISME 2015 - Information Science and Management Engineering III

ISME 2015 - International Conference on Information System and Management Engineering

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APPENDIX

Zhang Jianwei (1980-), male, post doctoral, research

interests include coastal geological, environmental

geology, etc.

[E-Mail:] dragonzjw@126.com

The Status and Disaster Losses of Seawater Intrusion in Kiaochow Bay Region