developing drainage as the basis of comprehensive control of drought, waterlogging, salinity and...

DEVELOPING DRAINAGE AS THE BASIS OF COMPREHENSIVE CONTROL OFDROUGHT, WATERLOGGING, SALINITY AND SALINE GROUNDWATERy

FANG SHENG* AND CHEN XIULING

Hebei Provincial Academy of Water Resources, Shijiazhuang, China

ABSTRACT

The North China Plain is short of water resources. The disasters caused by drought, waterlogging, salinity and

saline groundwater are the main restrictive factors for sustainable development of agriculture. The regulation of the

Haihe River and the excavation and dredging of main drainage rivers have remarkably improved the drainage

outlets to drain floodwater, excessive rainwater and saline groundwater into the sea. Exploiting groundwater,

including brackish and semi-saline water by tube wells, has the objectives to combat drought by making irrigation

possible in the spring, to lower groundwater levels before the rainy season, to increase percolation and underground

storage of rainwater, to reduce surface runoff, to leach salts from the soil by summer rainwater and to prevent

waterlogging, thus transforming the natural rainfall into available water resources. In autumn and winter river water

is diverted to and stored in deep ditches and canals to recharge groundwater and to promote the freshening of saline

groundwater. In this way, through the conjunctive use of surface and groundwater, the balance between exploitation

and supplementing of water resources in the area has been maintained, and the comprehensive control of drought,

waterlogging, salinity and saline groundwater, the sustainable utilization of water resources, the sustainable

development of economy and society, and a good eco-environment has been realized. Copyright # 2007 John

Wiley & Sons, Ltd.

key words: North China Plain; Haihe River; drainage; flood; waterlogging; drought; salinity; saline groundwater

Received 16 March 2007; Revised 18 September 2007; Accepted 18 September 2007

RESUME

La Plaine de Chine du Nord manque de ressources en eau. Les desastres provoques par la secheresse,

l’engorgement, la salinite et les eaux souterraines salines sont les principaux facteurs limitants du developpement

durable de l’agriculture. La regulation du fleuve Haihe et l’excavation et le draguage des principaux cours d’eau de

drainage ont remarquablement ameliore l’evacuation des crues, des exces de precipitations et des eaux souterraines

salines vers la mer. L’exploitation par forage des eaux souterraines, y compris les eaux saumatres et semi-salines, a

pour objectif de combattre la secheresse en permettant l’irrigation de printemps, d’abaisser les niveaux des nappes

avant la saison des pluies, d’augmenter la percolation et le stockage souterrain de l’eau de pluie, de reduire le

ruissellement de surface, de permettre le lessivage des sels par les pluies d’ete, et d’empecher l’engorgement des

terres, transformant ainsi les precipitations normales en ressources en eau disponibles. En automne et en hiver l’eau

des cours d’eau est prelevee et stockee dans de profonds fosses et canaux de facon a recharger les nappes et favoriser

la dilution des eaux souterraines salines. L’utilisation conjointe des eaux de surface et des eaux souterraines a ainsi

permis de preserver l’equilibre entre l’exploitation et la mise a disposition de ressources en eau dans le secteur, et de

parvenir a la maıtrise complete de la secheresse, de l’engorgement, de la salinite et des eaux souterraines salines, a

IRRIGATION AND DRAINAGE

Irrig. and Drain. 56: S227–S244 (2007)

Published online in Wiley InterScience (www.interscience.wiley.com) DOI: 10.1002/ird.370

*Correspondence to: Fang Sheng, Hebei Provincial Academy of Water Resources. 310 Taihua Street Shijiazhuang, P.R. China.E-mail: [email protected] drainage, base de la maıtrise de la secheresse, de l’engorgement, de la salinite et des eaux souterraines salines.

Copyright # 2007 John Wiley & Sons, Ltd.

l’utilisation durable des ressources en eau, au developpement durable de l’economie et de la societe, et a un

eco-environnement satisfaisant. Copyright # 2007 John Wiley & Sons, Ltd.

mots cles: Plaine de Chine du Nord; fleuve Haihe; drainage; inondation; engorgement; secheresse; salinite; eaux souterraines salines

INTRODUCTION

The North China Plain, located to the north of the Yellow River, belongs to a seasonal arid semi-humid continental

monsoon climatic region. Drought often occurs in spring, waterlogging in summer, then drought again in autumn

and winter. The tributaries of the Haihe and Luanhe rivers are distributed in the shape of a fan, their lengths are short

and they are characterized by a rapid flow. Their river courses in the plain area are shallow and wide, in the lower

reaches they are mostly above the ground surface. Throughout history, the peak floods of the five river systems of

the Haihe River Basin as they leave the mountain area have reached 10 000m3 s�1, while those in the middle and

lower reaches are only several hundreds of cubic metres per second. The lower reaches of the five river systems join

at the lower reach of the Haihe River (near to the river mouth) in Tianjin. When floods occurred, inundations or

dike breaches have taken place about nine times in ten years. Before the founding of the new China (1949),

inundations of an area of more than 3 million ha caused by historical floods have occurred over 10 times. Floods

have inundated Beijing five times and Tianjin eight times (Liu and Hou, 1982). The extensive plain area of the

Haihe River Basin was separated by the rivers into many large and small low-lying lands without any outlet for the

discharge of excessive rainwater. Once a rainstorm occurred, the crops would suffer from waterlogging over large

areas. Over geological history, a large area of saline groundwater was formed in the North China Plain as the

continent underwent salinization caused by a dry climate and seawater intrusion. Its area accounted for 61% of

the total area of the North China Plain (Figure 1). In all cases the saline–alkali lands were distributed around the

low-lying lands, along both sides of rivers, on flat slopes, in the saline groundwater region and the coastal area. At

the end of the 1950s, in order to develop irrigation to combat drought, a lot of water was diverted to and stored in the

plain area. Because of the absence of drainage facilities, the groundwater table had risen and a large area of

secondary salinization of soil occurred in the irrigation districts. The area of saline–alkali land increased by 50% in

1961 compared to the situation in 1958 (Wang et al., 1993), resulting in serious loss of agricultural production in the

North China Plain. In the Haihe River Basin an extraordinary flood occurred in 1963 and serious waterlogging in

1964; both made the hazards of waterlogging and salinity more serious (Fang and Chen, 2005b). Flood,

waterlogging, drought, salinity and saline groundwater have become the main restrictive factors for the sustainable

development of agriculture in the North China Plain. For the sustainable development of agriculture, economy and

society, it is necessary to harness the Haihe River and implement a comprehensive control of drought, waterlogging,

salinity and saline groundwater.

REGULATION OF THE HAIHE RIVER TO DRAIN FLOODWATER, EXCESSIVE RAINWATERAND SALINE GROUNDWATER

In order to regulate the Haihe River and make possible the comprehensive control of drought, waterlogging, salinity

and saline groundwater in the North China Plain, China’s Ministry of Water Resources has worked out The

Planning of Haihe River Basin and organized an investigation of soil and groundwater in the North China Plain.

The state has decided to initiate a programme of permanent control of the Haihe River. Reservoirs have been built in

the upper reaches to restrain floods and store water for flood control and developing irrigation, and since 1964 the

main drainage rivers to the sea have been excavated and dredged in the plain area year on year. Up to 1975, the five

tributaries of the Haihe River had their own outlets to the sea, and their discharge capacities of floodwater and

excessive rainwater into the sea increased by four and six times respectively as compared with those in 1964 (Liu

and Hou, 1982). Extensive drainage works have been developed in irrigation districts and the drainage systems to

drain floodwater, excessive rainwater and saline groundwater have been completed in the North China Plain

(Figure 2).

Copyright # 2007 John Wiley & Sons, Ltd. Irrig. and Drain. 56: S227–S244 (2007)

DOI: 10.1002/ird

S228 F. SHENG AND C. XIULING

The regulation of the Haihe River permitted the realization of an overall arrangement of drainage of floodwater,

excessive rainwater and saline groundwater, so that each has its own way out. Firstly, for the huge incoming flow of

floodwater, dikes were constructed to restrict the floodwater running on the floodplain and finally into the sea.

Secondly, combined with the construction of dikes for flood control, the main drainage rivers were opened up to

drain excessive rainwater or the floodwater of small streams. Thirdly, the drainage river courses have all been

dredged to a depth of 4–6m, so that they can be used not only to drain excessive rainwater but also saline

groundwater (Figure 3) (Fang and Chen, 2005b). These works have greatly improved the outlets to drain

floodwater, excessive rainwater and saline groundwater into the sea.

The significant drainage effects can be seen from the observation and analysis of the inflow of water and salt at

the section where water flows from the mountain area into the plain area and those of the outflow at the section

where water runs out of the plain area of the Haihe River Basin into the sea (1966–1981). 1977 was a wet year, the

precipitation was 691mm, of which 580mm occurred in the rainy season, the amounts of water and salt flowing

Figure 1. Map of mineralization of groundwater in the North China Plain (Zhu et al., 1990)


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DRAINAGE TO CONTROL DROUGHT, WATERLOGGING AND SALINITY S229

Figure 2. Map of the river course for drainage to the sea in the North China Plain (2000)

Figure 3. Section of a main drainage river (Fang and Chen, 2005b)


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from the plain area into the sea were more than those running from the mountain area into the plain area, the water

amount was 2.2 billion m3, and the salt amount was 7.6 million t. The North China Plain was in a state of

desalinization (Table I).

In the canal irrigation districts drainage works were constructed, which have changed the farmland from being

inundated by excessive rainwater and salt accumulation after waterlogging to conditions for salt leaching by

summer rainwater and drainage of saline groundwater after rainfall. During the period from 21 July to

30 September 1964, the precipitation was 439mm, the Longzhihe River downstream of the Shijin Canal Irrigation

District had drained 24 million m3 of excessive rainwater to the Fuyanghe River, the inundated area was reduced

and 40 000 t of salt were drained off. After drainage of excessive rainwater the deep drainage ditches continued to

drain saline groundwater (Fang and Chen, 2003a). In the period from October 1964 to September 1965, the

Longzhihe River had drained 13 000 t of salt. The salt drained off was 220 t km�2 in the Longzhihe River Basin.

In the Nanpi Pilot Area, located to the east of the South Grand Canal, the water and salt were drained off 7 times

in 6 years from 1974 to 1987 to the Dalangdian General Main Ditch and then into the sea. The grand total of salt

drained off was 1400 t km�2 (Table II, Fang and Chen, 2005a). Regulation of the Haihe River and development of

drainage works have provided the outlets for floodwater and excessive rainwater, which not only reduced the area

of inundated land, but also drained the harmful salt to the sea. That has laid the foundation for permanent control of

soil salinity. With irrigation developed on the basis of drainage, salt can be leached and drained off, and salt

Table I. Input of water and salt frommountain area into plain area and output from plain area into the sea at Beijing, Tianjin andHebei, of the Haihe River Basin (1966–1981)

Year 1977 1969 1976 1966 1968 1972

Water year wet sub-wet sub-wet normal ex. dry ex. dry

Annual precipitation (mm) 691 622 599 470 426 382Precipitation in July–Sept.(mm) 580 560 555 444 319 286P in % 20 23 30 46 90 93Water (billion m3):� flowing from mountain area 14.8 10.4 12.3 9.2 10.2 7.7� flowing from plain area to sea 17.0 7.3 5.6 5.3 1.0 0.6(þ), (�) �2.2 þ3.1 þ6.7 þ3.9 þ9.2 þ7.1Salt (10 000 t):� flowing from mountain area 438 411 387 315 417 302� flowing from plain area to sea 1 210 406 392 224 112 62(þ), (�) �767 þ5 �5 þ91 þ305 þ240

Source: Zhao Hongjun (1983).

Table II. Precipitation, water and salt drainage in Nanpi Pilot Area (Fang and Chen, 2005a)

Duration Drainagearea (km2)

Precipitation(mm)

Water drained(1000m3)

Average mineralization(g l�1)

Saltdrained (t)

Unit area saltdrained (t km�2)

1974: 22/7–30/8 4.53 570 365 3.83 1 397 3081975: 29/7–20/8 4.53 2 85 75 4.17 313 691976: 19/7–27/7 4.53 384 102 4.17 422 931977: 26/6–20/8 4.53 862 1 260 3.08 3 860 8531984: 9/8–16/8 4.33 179 67 1.18 80 181987: 3/8–4/8 4.33 149 17 1.48 26 61987: 26/8–3/9 4.33 189 132 1.56 206 48Total 2 010 3.27 6 310 1 400


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accumulation can be prevented after irrigation (Fang and Chen, 2003a). In 1980, not only was the secondary

salinization of the soil in the irrigation districts controlled, but also some of the original saline–alkali land was

reclaimed (Wang et al., 1993).

EXPLOITING AND UTILIZING GROUNDWATER INCLUDING BRACKISH ANDSEMI-SALINE WATER TO COMBAT DROUGHT AND FOR IRRIGATION

The North China Plain is short of water resources; especially in its eastern part, the water resource is only

150–190m3 per capita, which is far less than the Chinese average of 2180m3 per capita. To combat drought and

develop irrigation, groundwater has been exploited and utilized on a large scale since the end of the 1960s. Up to

the 1990s, 2 million power-operated wells were built and 25.3 billion m3 of groundwater were exploited; the

well-irrigation area reached 8 million ha in the plain area of Hebei, Henan and Shangdong provinces. The

exploitation of groundwater has greatly enhanced the capability to combat drought and promoted the sustainable

development of agriculture in the North China Plain (Chen Meifen, 1995).

The area of saline groundwater accounting for 61% of the total of the North China Plain, which occupies the

stratum of shallow groundwater and influences the rainwater and surface freshwater storage, was not used in the

past. As a result, water evaporated and salt accumulated which caused soil salinity. Since the 1980s, through

experiments and research work carried out by the Hebei Institute of Hydrotechnics, a breakthrough in the

technology of using saline water for irrigation was achieved. The brackish (2–3 g l�1) and semi-saline water

(3–5 g l�1) was used to irrigate crops by key watering when drought occurred, which increased soil moisture and

decreased the concentration and osmotic pressure of the soil solution, and controlled the soil solution concentration

in the root zone of the soil not exceeding the physiological tolerance of crops. According to the experiments at fixed

points in 10 years, the yield of double cropping of wheat and summer corn irrigated by semi-saline and brackish

water had increased by 1.2–1.6 times as compared with rainfed crops (Table III). The added salt in the soil caused

by irrigation with saline water can be leached and drained off by rainwater or freshwater irrigation in such a way

that no salt accumulation will occur in the root zone (Fang and Chen, 1997a). This can help to increase yield by

providing some key watering for wheat, which requires most water in the dry season, and support that the seedling

of corn and cotton may reach full stand before seeding in the dry spring every year. It means one half of farmland is

provided with irrigation water in the saline groundwater region, and brings the role of drought combat and yield

increase into full play.

At the beginning of the 1980s, the experimental results of using saline water for irrigation were applied with an

IFAD (International Fund for Agricultural Development) loan from the United Nations, developing drainage as the

basis for controlling the salt-affected soils in an area of 20 640 hawith low yields in the middle part of Nanpi County

(Fang and Chen, 1997b). Where the Nanpi Agricultural Development Project Area (NADPA) was established, the

irrigation area has doubled and the total agricultural production value and the income per capita increased threefold.

In 1986–2004, Nanpi County exploited 0.75 billion m3 of shallow groundwater, of which brackish and semi-saline

water was 0.36 billion m3. By 2004, the well irrigation area reached 23 700 ha. Up to 2005, the area of salt-affected

soils had been reduced by 75% in NADPA as compared with that in 1984 (Figure 4), and the saline groundwater was

freshened to some extent.

Table III. Crop yield (kg ha�1) irrigated with various qualities of water

Crops <1 g l�1 2–4 g l�1 4–6 g l�1 Non-irrigation

(1) Wheat 4 850 3 630 2 930 840(2) Summer corn 5 540 4 730 4 040 2 340(1)þ (2) 10 400 8 360 6 960 3 180(3) Spring corn 5 880 5 330 4 800 4 883(4) Soybean 1 700 1 250 960 915

Source: Chen Xiuling (1995).


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The improvement of the eco-environment of farmland has promoted the sustainable development of agriculture.

In Nanpi County, the total yields of grain and cotton increased to 135 000 and 13 100 t respectively in 2004, from

103 000 and 6790 t in 1986. The total annual income of agriculture increased to 762 000 million yuan (1US$¼7.7 yuan roughly), the annual income per capita increased to 2550 yuan in 2004, an increase of 4.4 and 7 times

respectively as compared with the income in 1986 (Table IV).

Figure 4. Distribution of salt-affected soils in the Nanpi Agricultural Development Project Area (NADPA) (1984–2005) (Fang et al., 2006)


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The technology for using saline water for irrigation has been applied and popularized extensively in the eastern

part of the North China Plain. Up to 2000, the total volume of brackish water utilized for irrigation was 1 billion m3

in Hebei Province (Li et al., 2005). The cycling and blending of saline water with fresh water for irrigation widely

used in Cangzhou, Henshui, Xingtai, Handan, Xinxiang, Dezhou and Tianjin cities, has strongly promoted the

sustainable development of agriculture in these regions.

RATIONAL REGULATION OF GROUNDWATER DEPTH TO TRANSFORM NATURALPRECIPITATION INTO AVAILABLE WATER RESOURCES

The dynamics of groundwater depth is the concentrated reflection of growth and decline as well as transformation

between atmospheric precipitation, surface water, soil water and groundwater. Rational regulation of groundwater

depth is the key for expanding utilization of rainwater. The required dynamics of groundwater depth in different

seasons are: (1) the critical depth of groundwater for salinity control in the dry season (2–3m), to reduce the

phreatic water evaporation and to prevent salt accumulation in the soil; (2) the depth for preventing waterlogging

and rainwater storage before the rainy season (4–6m), to increase rainfall infiltration, reduce surface runoff,

enhance the functions of salt leaching by summer rainwater and groundwater freshening; (3) the depth for wet

resistance of crops in the rainy season (0.5–1m). Usually it is required to drain off the accumulated water due to

rainfall and lower the raised groundwater table below the depth for aeration of crops (Fang and Dai, 2002).

Exploiting and utilizing shallow groundwater, including brackish and semi-saline water, in the eastern part of the

North China Plain has the functions of increasing underground storage capacity, regulating groundwater depth at

critical dynamics, and transforming the natural precipitation into available water resources. The total exploited

amount of groundwater in NADPA was 6 million m3 before its establishment and it reached 13.8 million m3 in

1987. Well irrigation simultaneously played the role of well drainage, and lowered the groundwater table. The

groundwater depths dropped below 3m before the rainy season (June) in 1988, as compared with the same period in

1985, the area with depths of 2–3m was reduced by 77%, the area with depths of 4–6m increased by 53% (Table V,

Figure 5). The groundwater depths in 1986–1988 were 2.78–3.73m in spring (March), 4.48–5.03m before the rainy

season (June) and 1.50–2.95m after the rainy season (September) (Figure 6), which was in accordance with the

indices of critical dynamics of groundwater depth. It shows that the project has created the conditions for

reasonable control and utilization of water resources.

Table IV. Development of agriculture and economic income of Nanpi County

Year 1986 1993 2003 2004

Precipitation (mm) 394 449 720 489Total population 294 000 297 000 297 000 299 000Grain area (hm2) 48 800 50 500 29 600 28 200� grain yield (thousand kg) 103 000 153 000 127 000 136 000� grain per capita (kg) 351 514 428 483Wheat area (hm2) 22 600 24 100 14 300 13 400� wheat yield (thousand kg) 52 700 71 400 62 600 62 600Corn area (hm2) 14 500 16 200 14 100 14 100� corn yield (thousand kg) 37 400 65 600 60 800 71 900Cotton area (hm2) 9 850 14 800 18 100 18 600� cotton yield (thousand kg) 6 790 3 740 10 500 13 100� cotton per capita (kg) 23 13 36 44Total income (thousand yuan) 143 700 480 000 714 000 763 000Net income per capita (yuan) 307 581 2 410 2 550

Source: Fang et al. (2006).


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Reducing phreatic water evaporation

The amount of phreatic water evaporation is closely related to groundwater depth. In the area of light sandy loam,

when the groundwater depth is at 1m, the amount of phreatic water evaporation is six times as high as that with a

groundwater depth at 2.5m (Figure 7). In the NADPA, according to the average groundwater depth in 1984–1986

(2–3m), the exploitable amount of phreatic groundwater was 4.3 million m3. The groundwater depths in

1986–1988, which were regulated at critical dynamics (2.5–5m), resulted in the exploitable amount of

13.2 million m3. This means that a total of 8.9 million m3 of available water resources was recaptured from phreatic

water evaporation.

Reducing surface runoff

When combating drought by irrigation in the spring, a lot of shallow groundwater, including brackish and

semi-saline water, had been extracted. This had increased the available storage in the aquifer before the rainy

Figure 5. Groundwater depth (m) in the Nanpi Agricultural Development Project Area (NADPA) (1986–1988)

Table V. Influence to groundwater depth by exploitation of groundwater in NADPA

Groundwaterdepth

May 1984 June 1985 June 1988 March 1989 Spring March1989 comparedwith May 1984(þ) or (�)

Before rainy sea-son June 1988compared with

June 1985 (þ) or(�)

(m) ha % ha % ha % ha % ha % ha %

<1 0 0 134 0.7 0 0 0 0 0 0 �134 �0.71–2 1 600 7.8 3 140 15.2 0 0 0 0 �1600 �7.8 �3 140 �15.22–3 6 440 31.3 15 800 76.5 0 0 509 2.5 �5930 �28.8 �15 800 �76.53–4 12 600 60.9 1 580 7.6 9 620 46.6 13 100 63.6 þ578 þ2.7 þ8 040 þ39.04–5 0 0 0 0 11 000 53.1 6 210 30.1 þ6 210 þ30.1 þ11 000 þ53.15–6 0 0 0 0 64 0.3 698 3.4 þ698 þ3.4 þ64 þ0.36–7 0 0 0 0 0 0 82 0.4 þ82 þ0.4 0 0


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season, which increased the percolation of rainfall in the rainy season, it reduced the surface runoff, and prevented

the occurrence of waterlogging. Simultaneously the natural rainfall was transformed into available water resources.

The observation and research results have shown that the runoff decreased with the drop of the groundwater table

(Figure 8, Table VI) (Fang and Dai, 2002). The groundwater depth was at 1.1–2.5m before the rainfall in

1974–1977, the PþPa (the rainfall P plus the antecedent rainfall Pa) values of the observed individual rainstorm

events varied from 157 to 244mm, and the depths of runoff varied from 18 to 47mm, then waterlogging occurred.

In 1984–1987, before the rainfall, the groundwater depth was from 2.7 to 4.6m, when the rainfall events with

PþPa ranging from 88 to 236mm occurred, the runoff was 0–30mm. In the period of the 1970s and 1980s, the

groundwater depth was in the range of 1–5m, according to the experimental data, when the groundwater table

dropped by 1m, the runoff decreased by 12–25mm. 1987 was a sub-wet year with a total annual precipitation of

735mm, in which 509mm fell during the rainy season, and because of the low groundwater table, no waterlogging

occurred (Fang and Dai, 2002) .On 26 August there was a 6-hour rainstorm of 189mm, in the northern part of the

Figure 7. Relationship between evaporation of phreatic water and depth of groundwater (Fang and Chen, 2003a)

Figure 6. Process of dynamics of groundwater depth in the Nanpi Agricultural Development Project Area (NADPA) (1986–1988) (Fang et al.,2004)


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Nanpi Pilot Area, the groundwater depth was at 4.62m before the occurrence of the rainstorm, and no runoff

occurred (Table VI).

The relationship between runoff depth (R), rainfall (P þ Pa) and groundwater depth (H) was found as:

R ¼ P0 1� H

Hm

� �n

where

R¼ runoff depth (mm)

P0 ¼P (a rainfall)þPa (antecedent precipitation) (mm)

H¼ groundwater depth before rainfall (m)

Hm¼ extreme groundwater depth, i.e. under various P0, when R is zero, the corresponding groundwater depth

(m), Hm¼ 0.016P0 þ 1

n¼ empirical exponent¼ (0.0018P0 � 0.08) Hþ 3.63.

Increasing rainfall infiltration and recharge to groundwater

According to the research in Nanpi and the area east of the South Grand Canal, in a normal year the precipitation

was 434mm in June to September, the maximum rainfall percolation to groundwater occurred when the

groundwater depth was about 4.5m before the rainy season (Figure 9). When the groundwater depth was less than

4.5m in the period before the rainy season, if the groundwater table dropped by 1m, the rainfall infiltration

recharged to the groundwater would increase by 6–22mm. In 1986–1988 the average groundwater depth in

Table VI. Influence of groundwater depth to rainfall infiltration and runoff

Observed section Area Date H P Pa PþPa R Groundwater depth2 days after rain (m)

(km2) (m) (mm) (mm) (mm) (mm)

South branch ditch 4.51 23/7/1977 1.10 102 54.5 157 47.2 0.01South branch ditch 4.53 5/8/1977 2.05 123 121 244 44.7 0.15North branch ditch 15.1 29/7/1975 2.36 186 8.2 195 24.5 0.65South branch ditch 4.51 3/8/1987 3.20 149 12.0 161 4.0 1.73North branch ditch 15.1 26/8/1987 4.62 189 47.7 237 0 1.92

Source: Fang and Dai (2002).

Figure 8. Relationship equation of R� (PþPa)�H


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NADPAwas greater than 3m, in which the area with depths of 4–6m accounted for 53% in NADPA. In that year a

lot of groundwater had been withdrawn and used, due to the rainwater supplement in the rainy season, the

groundwater table rose by 1.75m. By deducting the amount of water withdrawn and that due to groundwater

evaporation, the exploitable amount increased by 85mm yr�1, which supplied the groundwater source in autumn

and the next spring, and freshened the groundwater quality (Fang and Dai, 2002).

Qi Weifang (1990) derived the following relationship equation between recharge to groundwater (Pr), a rainfall

(P) and groundwater depth before rainfall (D):

Pr ¼ Prm

D

Dm

� �b 1� DDm

ð Þ

Dm ¼ 0:31P0:52

Prm ¼ 3:32� 10�3P2 � 8:73� 10�6P3 þ 0:51P

b ¼ 3:88� 10�6P2 � 9:05� 10�4Pþ 0:76:

where

P¼ a rainfall

Pr¼ recharge to groundwater by a rainfall infiltration

D¼ groundwater depth before rainfall

Prm¼when P is a definite value, the maximum recharge to groundwater by rainfall infiltration

Dm¼ the corresponding groundwater depth with Prm

b¼ an empirical exponent

Suitable range of the above formula: a rainfall <344mm, D< 8m.

The above findings from the research in the 1980s were confirmed by recent field observation data. In Nanpi

County a drought occurred in spring 2003, and a total of 49 million m3 of shallow groundwater was pumped for

irrigation. The groundwater table was lowered to below 5–6m before the rainy season. Precipitation of

118–160mm in 8 h occurred on 23 July; all of the excess rainwater had infiltrated underground and no runoff

accumulated in the farmland. There was also a heavy rainstorm over the whole county on 30 July, and the

precipitation was 139–176mm. Because the underground capacity of the aquifer had been emptied before the

rainfall, and the precipitation replenished to groundwater after the rainfall, the groundwater table rose by 1.5m

from a depth of 5.8m to 4.3m. The rainstorm not only caused no hazard to crops, but also supplemented the soil

moisture. On 9–11 October, a larger rainstorm occurred with a precipitation of 123–190mm, no waterlogging

occurred because the groundwater depth had been regulated appropriately. The excessive rainwater was drained

Figure 9. The relationship between rainfall percolation, precipitation in the rainy season and groundwater depth before the rainy season (Fangand Dai, 2002)


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into ditches and stored for utilization, the groundwater depth rose by 1.8m from original 4.3m to 2.5m (Figure 10).

Thus, the three heavy rainfalls and rainstorms caused no waterlogging and most of the rainwater recharged the

groundwater and was transformed into available water resources (Fang et al., 2006).

In the eastern part of the North China Plain, because of the exploitation and utilization of groundwater, including

brackish and semi-saline water, the stored amount of groundwater has been decreased so that more rainwater can

percolate to replenish it. As a result a larger amount of irrigation water extracted from the aquifer can be

compensated by rainfall recharge and the previously saline water can become an exploitable water resource. The

area of brackish and semi-saline groundwater of less than 5 g l�1 is 36 300 km2 in the North China Plain. According

to rough estimates, based on an average annual rainfall percolation of 100mm (100 000m3 km�2) and an

exploitation coefficient of 0.8, the increased annually exploitable resources due to utilization of previously saline

water would be 2.9 billion m3 (Zhang Weizhen, 2003).

DIVERTING AND STORING RIVER WATER IN AUTUMN AND WINTER TO RECHARGEGROUNDWATER FOR WATER SOURCE SUPPLEMENT

The North China Plain is seriously short of surface water, all the river flow is drying up in spring, but there is some

river water source after the rainy season in autumn and winter. By means of drainage ditches, canals and ponds to

retain and store such water to recharge the groundwater, an effective approach for increasing water resources has

been created (Fang and Chen, 1997b). The drainage ditches and canals are connected to river courses, which can be

used for irrigation and drainage. The river water can be diverted to any place in the controlled range of the canals

and ditches. The canals and ditches can be taken as a regulation reservoir, in which river water can be stored in

winter and used in the next spring for pumping irrigation in time with proper water quantity. Recharging

groundwater by river water is beneficial for the freshening of groundwater and enables the balance between

exploitation and supplementation of groundwater to be kept. Langfang City, situated in the lower reaches of the

Haihe River, successfully used deep canal networks, ponds and pumping stations to divert and store seasonal

surface water for groundwater recharging. In 1975–1987, the amount of water diverted and stored was 5 billion m3;

the average annual amount was 390 million m3. The water storage was 55mm km�2 yr�1, allowing the range of

Figure 10. Precipitation, river water diversion, process of groundwater depth in Nanpi County (2003–2004) (Fang et al., 2006)


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variation of the groundwater table to go to 3.44m from the original 1.03m, and the water regulation capacity of the

shallow groundwater aquifer was enlarged (Fang and Chen, 1997b).

In order to supply water to the eastern part of the Haihe River Plain, the Yellow River Diversion Project was

undertaken in the region fromWeishan in Shangdong Province to Linxi in Hebei Province, in order to transfer water

to Hebei Province and Tianjin city. Since 1994, the water has been diverted in the non-irrigation season from

November to February every year; 0.5 billion m3 of water can be diverted to Cangzhou, Hengshui and Xingtai

cities. In Nanpi County the river water was diverted from the Yellow River, the Zhangwei New River and the

Xuanhuihe River in 1984–2004, and the average annual diverted amount was 26.4 million m3 and the average

annual irrigated area was 6400 ha. In 2003–2004, 82 million m3 of water were diverted, the irrigated area was

8670 ha, and a lot of water was recharged to the groundwater; the groundwater table rose to about 2m from original

5–6m (Figure 10). In this way the water for combating drought and for irrigation in autumn, winter and the

following spring has been ensured and the balance between exploitation and supplementation of groundwater has

been maintained (Fang et al., 2004).

FRESHENING SALINE GROUNDWATER

Under conditions of drainage of excessive rainwater and saline water, exploiting shallow groundwater, including

brackish and semi-saline water for irrigation in great quantities, and recharging groundwater by fresh water

including rainwater and river water, can enhance the circulation and replacement of saline water and fresh water,

and promote the gradual freshening of saline groundwater.

In 1974, the Hebei Institute of Hydro-techniques began to carry out an experiment of utilization and freshening

of saline groundwater in the Nanpi Pilot Area. In 1980, it carried out a fixed position experiment on using saline

water for irrigation in spring and draining saline groundwater and recharging groundwater by rainwater in summer.

Over 10 years (1980–1989), the saline groundwater in the experiment field had obviously freshened year by year.

As compared with the same period before the rainy season (March–June), the mineralization of groundwater of

4–7.8 g l�1 in 1982, decreased to 1.2–1.33 g l�1 in 1988, of which that of the surface groundwater decreased to

1.2–2.5 g l�1 from 4.8–5.1 g l�1; that at the depth of 5m, decreased to 1.2–2.4 g l�1 l from 5.1–5.3 g l�1; that at the

depth of 10m, decreased to 2.6–3.3 g l�1 from 5.7–7.8 g l�1 (Table VII).

Table VII. Variation of mineralization (g l�1) of groundwater in Nanpi experimental field of Hebei Institute of Hydrotechnics(1982–1988)

Date Ground- waterdepth m

Well no. 12 Well no. 14 Well no. 15 Annual precipitation(mm)

Surface 5m 10m Surface 5m 10m Surface 5m 10m

Jun 1982 2.9 5.1 5.3 7.8 4.8 5.1 5.7 4.8 5.2 6.4 380Sep 1982 2.0 5.6 5.7 11.5 3.8 3.6 3.6 4.7 5.8 6.9Jun 1983 2.7 4.6 5.1 7.1 2.9 3.3 4.2 5.8 6.3 6.5 405Sep 1983 2.2 4.1 5.8 7.0 3.7 3.9 4.1 3.7 4.5 12.0Jun 1984 3.0 3.8 3.8 7.3 3.4 3.9 4.1 1.4 4.2 11.7 583Sep 1984 1.5 3.5 3.2 6.1 2.0 3.8 5.0 2.7 4.0 11.3Jul 1985 1.8 2,0 2.1 2.9 2.0 2.3 4.7 5.0 5.0 10.6 555Sep 1985 1.0 2.4 3.3 4.1 2.7 3.3 5.1 2.8 3.9 9.1Jun 1986 2.9 4.0 3.9 5.8 3.0 3.2 4.0 4.8 4.8 10.1 397Oct 1986 3.9 3.0 3.3 5.2 2.7 3.4 4.6 3.8 4.5 12.1Mar 1987 3.5 2.6 2.6 3.9 1.4 2.4 2.4 3.3 3.2 8.6 736Aug 1987 2.5 0.3 0.6 2.2 1.2 1.4 1.6 0.3 1.0 1.6Mar 1988 2.5 2.5 2.4 3.3 1.2 1.2 2.6 2.1 2.1 2.8 471Nov 1988 1.5 3.5 3.4 3.8 1.1 1.8 3.8 1.1 1.3 3.1

Source: Fang Sheng and Chen Xiuling (2003).


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The NADPA, established in 1983, exploited and utilized a lot of groundwater including brackish and semi-saline

groundwater; due to the lowering of the groundwater table, the percolation of rainfall increased. It also diverted and

stored a large amount of river water to recharge groundwater and promote the freshening of saline groundwater. The

areas of fresh water and saline water in the NADPA are shown in Figure 11 and Table VIII. In June 1989 as

Figure 11. Variation of mineralization of groundwater (g l�1) in the NADPA (1986–1989)

Table VIII. Variation of groundwater mineralization in NADPA (area with different mineralizations in %) (1985–1989)

Mineralization(g l�1)

June 1985 June 1986 June 1987 June 1988 June 1989 June 1989 comparedwith June 1985

<2 23 20 29 30 36 þ132–3 24 30 25 35 33 þ93–5 25 24 23 24 19 �65–10 18 16 15 8 9 �9>10 10 10 8 3 3 �7

Table IX. Variation of groundwater mineralization (g l�1) in Nanpi groundwater monitoring area (area with differentmineralizations in %) (1974–1988)

Year Groundwater surface Depth of 5m Depth of 10m

<2 2–3 3–5 5–10 >10 <2 2–3 3–5 5–10 >10 <2 2–3 3–5 5–10 >10

1974 20 37 17 10 16 4 33 41 16 6 4 23 41 23 91977 33 22 18 21 6 19 30 26 20 5 5 18 37 27 131980 32 19 22 21 6 30 25 28 14 3 8 12 24 47 91984 31 26 14 23 6 10 42 31 16 1 7 31 33 23 61986 32 30 26 9 3 20 50 18 11 1 10 22 37 22 91988 50 23 17 10 0 37 35 20 7 1 49 26 16 5 4

Source: Fang and Chen (1997a).


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Figure 12. Mineralization of groundwater of the monitoring area in the Nanpi Pilot Area (g l�1) (1974–1980–1988)


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compared with June 1985, the area of fresh water increased by 13%, the brackish water increased by 9%,

the semi-saline water decreased by 6%, the saline water decreased by 16%. In 1987, a sub-wet year, the rainfall

was 509mm in the rainy season. The area of fresh water in June 1989 increased to 36% from 20% in June 1986

(Table VIII). This shows that precipitation is the main source of fresh water percolating into the ground.

Therefore regulating the groundwater depth at critical dynamics and striving for the maximum recharge of

rainfall is the key to increase the underground freshwater source and to promote the freshening of

groundwater.

The scientific experiment on utilization and freshening of saline groundwater in 1974–1988 through 6 sub-dry

years, 5 normal years, 2 sub-wet years and 2 wet years, has achieved significant success. The results of groundwater

mineralization monitoring show that, from 1974 to 1988, at the groundwater surface, the area of fresh water

increased to 50% from 20%, the former area of saline water with mineralization>10 g l�1 accounting for 15% had

disappeared. At a depth of 5m, the area of fresh water increased to 37% from 4%. At a depth of 10m, the area of

fresh water increased to 49% from 4% (Table IX, Figure 12). The freshwater body from the depth 4–8m increased

by 639 000m3 in the monitoring area, the modulus of exploitable amount of fresh groundwater increased by

15 000m3 km�2 yr�1 (Fang and Chen, 1997b).

CONCLUSIONS

1. The development of drainage is the basis for the comprehensive control of drought, waterlogging, salinity

and saline groundwater in the North China Plain. The regulation of the Haihe River, and the excavation and

dredging of the main drainage rivers have allowed the outlets to discharge floodwater, excessive rainwater

and saline groundwater into the sea. The discharge capacities of floodwater and excessive rainwater have

been increased by 4 and 6 times respectively as compared to those before regulation. The salt disposed out

simultaneously with drainage of floodwater, excessive rainwater and saline groundwater has also been

greatly increased;

2. Exploitation and utilization of groundwater including brackish and semi-saline water at large scale, not only

has benefits for combating drought and increasing yields, but also functions as tubewell drainage, to lower the

groundwater level, limit salt accumulation in the soil, control secondary salinization in irrigation districts and

reclaim the saline–alkali land;

3. Diverting and storing river water in autumn and winter has the functions of recharging the groundwater

source and promoting the freshening of saline groundwater. Conjunctive use of surface and groundwater

helps to keep the balance between extraction and recharge of aquifers;

4. Under conditions of both ditch and well drainage, using saline groundwater for irrigation, not only prevents

salt accumulation in the root zone of the soil, but also increases the recharge of rainwater and river water to

groundwater and significantly promotes the freshening of saline groundwater year on year. The research on

utilizing and freshening of saline groundwater in the Nanpi Pilot Area has achieved significant success. It

breaks down the traditional limits that only fresh water (< 2 g l�1) can be used for irrigation, and

demonstrates that by using brackish (2–3 g l�1) and semi-saline water (3–5 g l�1) to irrigate crops for

key watering when drought occurs, the yield can be increased by 1.2–1.6 times than that of rainfed crops.

Through 10–15 years of experiments, the area of the former saline groundwater with mineralization greater

than 10 g l�1 accounting for 16% of the monitoring area had disappeared, the freshwater area increased to

50% from 20%, and the modulus of exploitable amount of fresh groundwater increased by

15 000m3 km�2 yr�1 in the monitoring area;

5. Using the soil and phreatic aquifer as an underground reservoir to regulate precipitation, soil water,

groundwater and surface water, according to the critical dynamics of groundwater depth as the regulating

index, has the benefits of effectively increasing rainfall percolation, reducing loss of runoff, leaching soil

salinity and freshening saline groundwater, thus to transform natural rainfall and surface runoff into available

water resources. Based on the actual observed data, empirical formulas were derived for the relationship

between surface runoff and recharge of rainfall to groundwater respectively, and the groundwater depth

before rainfall under different conditions of rainfall P or PþPa;


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6. Through comprehensive measures for the control of drought, waterlogging, salinity and saline groundwater,

the sustainable utilization of water resources, the sustainable development of the economy and society, and

the harmonious coexistence of people and nature can be realized.

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