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（2003年11月
中国·杭州）
中国大陆岸线，北起鸭绿江口，南至中越交界北仑口，总长18000km。如计入岛屿岸线则总计32000km。海岸带面积35万km2，其中潮上带面积约10万km2，滩涂2万km2，0~20m以内
海面积15.7万km2，其中0~15m12.4万km2，0~10m6.3万km2，0~5m等深线区域2.7万km2。浅海滩涂面积广阔，开发潜力巨大。平均每年入海迳流量17243亿m3。每年平均入海泥沙量约20亿吨。
我国海岸线上，大小不同类型各异的河口1800多个。其中仅河流长度在100km以上的河口就有60多个，另外，有海弯160多个。水陆集疏运条件良好，有一定的避风条件，很多具有较稳定的深水岸线和海底深槽，港口资源开发利用较早，但河口港址的缺点是河口有拦门沙，需进行整治，才好达到一定通航等级。有些河口还可利用高潮提高通航能力，如长江口平均潮差2.67m，珠江河口1.69m，海河口2.15m。
展望21世纪，为开拓人类生存空间，日本已开发人工岛和海上机场、城市。今后海上机场，海底仓库和储油储气设施将会兴建，随着海底隧道、海上桥梁的兴建，许多岛屿资源也将得到充分开发与利用。
河口是江河和海岸的交会处，它既有江河带来的洪水和泥沙，又受到海洋风暴潮和咸水盐碱化的威胁，又是淡水、咸水交会处，带来无限生机和丰富的营养，由此形成多种生物资源。如长江口的中华绒毛蟹苗和鳗鱼苗资源等。也是刀鱼、鲥鱼等名贵鱼类的回游通道。而江河泥沙的逐年淤积，使浅海逐步成滩涂湿地，又逐步成为陆地，造就世界上众多的河口三角洲。这正是人类繁衍生长的好地方。正是几千年来江河泥沙的淤填和中国历代人民兴修水利等活动，才造就了约近2亿亩的长江中下游平原、珠江三角洲、黄淮海平原、辽河平原等等占中国耕地1/10左右的肥沃耕地，养育了中国几亿人口。人类对河口和海岸的认识，也是随历史进程不断提高的。从农业社会的鱼盐之利，到近代的港口经济；特别是近20多年来海岸油气资源的发现与开发，随着经济全球化的进程，外资进入和对外开放、外贸经济的发展，中国对河口、港口海岸的重要性，对利用国内、国际两种资源、两个市场的重要性，正在不断加深、深化。因此对河口的认识，不能局限于河口本身，要从国民经济全局来衡量，要与全国生产力布局与对外开放形势相结合，要从长江三角洲和中下游平原，珠江三角洲与长江、珠江、黄河、欧亚大陆桥、国民社会经济布局来观察。河口与江河、三角洲密不可分，与江河、与海洋密不可分，与社会经济发展、环境生态密不可分。
近5年来全国主要江河流域规划均已修订，并经国务院审查批准。海洋功能区划也已审批。但河口及三角洲海岸带综合规划尚有些滞后，亟待列入议程，早日组织水利、水运、水产、国土、城建、海洋、环境、林业、旅游、油气、盐业等有关部门合作配合，共同制订。特别是包括港、澳在内珠江河口三角洲综合水利规划和长江口、钱塘江口，包括舟山群岛、长江口北岸、苏北滩涂等在内的长江三角洲水利综合规划，以及京、津、冀、黄河口、海河、滦河、辽河在内的环渤海水利综合规划等都亟待进行。
中国几千年来劳动人民创造了河口三角洲地区开发的良好经验。如长江三角洲的圩田、河网；珠江三角洲的桑基、蕉基鱼塘等等，创造了人工与自然相结合人工湿地，养育了几千万人口。但是近二十年来，大规模的围垦滩涂、围海；港口、油轮、河口建闸、采沙、采石、海岸工程和海上采油气平台等等人类活动，造成了环境生态方面负面影响严重。如不少已围垦的滩涂，由于缺乏淡水和水利设施不配套，长期围而不垦。南方大量红树林丧失，80年红树林约占5万公顷，现只剩下2万公顷。海南岛1/4海岸原是珊瑚礁海岸，80%遭到不同程度破坏。北方河流因水资源短缺，出现断流，河口大量建闸，河口渔场外移、消失，回游鱼、虾、蟹绝迹。近海和海湾围垦、海水养殖业发展，潮间带贝类资源和鱼、虾、蟹、藻等资源衰退，围垦和虾田养殖，使沿海自然滩涂湿地减少近一半。特别是每年有工业、生活污水约80亿吨入海，加上油轮溢油事故，使渤海、长江口、珠江口、钱塘江口、舟山群岛、大连弯、胶州湾等处近海水污染已经相当严重，赤潮频繁发生，已造成严重的环境和生态危机。珍稀海水动物如中华白海豚、鲸类、海牛、斑海豹、海龟、海马、以及麒麟菜等珍贵的藻、贝类资源已逐渐消失，面临灭绝危险。同时长江口、珠江口、海河口等淤积严重，影响泄洪和港口水运事业的发展。特别是渤海是我国内海，面积仅7万km2，水深平均20m，亟待保护。
几点看法：
1、珠江三角洲。由于1915年，1994年等大洪水和台风、风暴潮的威胁，枯水期广州、南海、番禺、顺德等城市缺水，水污染严重；必须完善城市和西江、北江等十大堤围防洪排涝体系建设，修建大藤峡水利枢纽，结合正在修建中的红水河龙滩水库、右江百色水库和已建的北江飞来峡水库，共同构筑珠江流域防洪河综合利用水利体系。在此基础上，北江、西江汇合处思贤滘河段整治和枢纽修建，将增加北江三水市以东下游和广州等河网区枯水流量，为改善广州、顺德等城市水环境有重大效益。在西江来大洪水时，保障珠三角防洪安全。同时珠江八大口门，滩涂逐年淤高，需要整治，保持洪道、航道畅通。
现在除香港、广州黄埔港外，东侧有盐田港、大亚湾澳头港；西侧有澳门、蛇口港和珠海高拦港，再加上将建设的番禺南沙港等，已构成环绕珠江口中部和东、西侧港口群，随着香港、深圳西通道的建设和跨珠江口的香港、澳门、珠海大桥的建设，珠江三角洲区域以香港、澳门、广州为龙头的社会经济发展将更进一步繁荣。
2、长江河口希望与钱塘江河口、舟山群岛深水港口群统一规划研究。目前长江口整治工程是必要的，不仅关系到上海港，而且与长江干流沿岸港口、航运关系密切。长江口深水航道整治一期工程已完成，正进行第二期工程，从深水港口资源来看，上海正在大小洋山建深水港，舟山群岛有深水港湾30多处，钱塘江河口滩涂资源广阔，宁波至上海的乍浦～慈溪公路大桥将修建，加上南通洋口深水港建设和上海至崇明岛穿越长江口水下通道和苏通长江大桥的建设，长江口、钱塘江口地区将能形成世界最大的深水港群，也是整个长江流域的对外门户。
为解决太湖水污染问题，除大力进行环湖城镇污水处理厂建设和尽力治理面源污染外，调长江水入太湖，加大太湖水循环是个重要措施。除望虞河抽水引江和镇江至江阴长江各闸引水外，建议研究自芜湖通过固城湖，东坝，胥河引长江水入太湖的方案。在枯水期引水阳江、青戈江部分迳流入固城湖，维持无太水运通道。
3、环渤海地区。天津塘沽新港，和北侧的秦皇岛港，京唐港，南侧的黄骅港，已形成北京、华北的门户，山东省的青岛港、烟台港，以济南、山东省为腹地。大连港、营口鲅鱼圈港、葫芦岛港，以辽宁和东北、内蒙古东部为腹地，已形成环渤海的港口群，将是中国纪长三角、珠三角后又一个经济增长区和城市群。
黄河河口三角洲。位于渤海湾和莱州湾之间，以宁海为顶点，北起套尔河口，南至支脉沟口，面积约6000多km2，扇形地区，自1885年黄河夺大清河入渤海以来，在近代三角洲范围内，决口改道50多次，其中较大改道10次，基本上在三角洲上普遍行河一次。
由于年降雨少，黄河迳流量小，70年代以来常断流，缺水。三角洲土地盐渍化严重，广阔盐碱滩涂缺乏淡水，人畜饮水十分困难，因此历史上人烟稀少，自从60年代末，胜利油田开始开发后，黄河河口堤防开始修建，平原水库开始建设，黄河入海流路逐趋稳定。自1976年河故道改走现在河道以来，已经稳定约30年。黄河河口三角洲首先是稳定入海流路，防洪与防风暴潮问题。其次是解决淡水水源，修建众多平原水库。再是广阔盐碱地的引洪淤灌，井排、井灌，抽咸换淡，洗盐和土壤改良问题。第四是交通，包括铁路、公路、海港、机场等。以上四大问题，需要下大力气进行水利为中心基础设施建设。三角洲水土资源开发，首先是黄河的可供水量，在分配给山东70亿m3水量中，山东分配给东营市可供水量为7.8亿m3，而1995年河口地区实际引水量14亿m3，其中东营8.6亿m3。黄河泥沙年均填海造陆23.8km2，河口区现有耕地448万亩，占37.8%，盐碱荒地258万亩，关键受制于水资源和如何利用黄河泥沙淤灌改良盐碱地问题。另外，还有滩涂470多万亩，其中自然保护区230万亩。本区油、气、盐、卤水资源丰富，土地广阔，林业、草地资源丰富，发展造纸业，畜牧业石油化工、盐化工，海水养殖业等等有巨大潜力，结合引洪淤灌，打井抽咸换淡，将来结合南水北调，是一块潜力大、待开发的河口三角洲。
4、关于北方河口建闸问题。华北平原由于水资源匮缺，各河口大都建河口挡潮闸，由此引起的闸外淤积问题严重。典型的如海河河口1958年建档潮闸后，为蓄淡水，几乎全年关闭，闸下淤积严重，河口段河床抬高，每年需清淤约50多万m3，海相泥沙淤积，排沙场地困难。其北部不远永定新河（排洪河道）北塘河口虽未建闸，但由于常年无迳流入海，在海潮涨落河段范围内，海相泥沙淤积问题也难以解决，正在进行河口建闸可行性研究。辽河河口也有类似情况。许多中小河口建挡潮闸后，切断了迳流，减少河口原有纳潮量，闸下游发生严重淤积，航道堵塞，部分中小港口失去原有功能，甚至成为废港。对于这一普遍存在的问题，海河水利委员会，研究海河口、北塘永定新河口、独流减河口的整治规划，海河口河道右侧修建突堤入海与塘沽新港突堤平行，直到-5m~-10m深水处，切断海洋泥沙沿海岸回流河口河道，再结合河口航道疏浚等措施，维持河口洪道。由于河流除汛期外，常年无迳流入海，因此河口泥沙淤积问题，亟待合理利用汛期洪水冲沙、拉沙，冲刷河道清淤，因地制宜地逐个加以解决。
总之，河口问题，首先是河口三角洲地区的整治规划，重点是防洪、防风暴潮、防台风；排涝防咸，洪道、航道整治和疏浚，保证洪道和航道畅通。其次是江河，特别是河口城市和农村淡水资源的供给和水污染防治，河口和近海水污染主要来自河流等陆源污染。三角洲城镇污水和禽畜养殖污水、农村面源污染和沿海滩涂水产养殖污染亦是重要污染源，需要重视河口三角洲广大河网地区内河的水污染防治。要按照河口和近海海洋水环境容量；江河迳流、潮流和水体自净能力，确定纳污总量，然后逐级上推，限制江河河口和河道中、上游各段的排污总量，按流域进行水污染防治。第三，河口和近海环境、生态和自然资源保护。河口生物资源丰富，滩涂湿地是生物多样性鸟类、鱼类、蟹、贝类、回游等生物的产卵、孵化场所，一旦破坏，影响深远，需要大力保护。河口及三角洲水利综合规划，需要各有关部门共同合作配合，制定综合统一规划，统一规划海陆发展，协调各利益主体之间的关系，实施综合保护、综合开发。需要国家计划委、水利、水运、水产、国土、城建、海洋、农牧业、环境、林业、旅游、油气、盐业等有关部门通力合作，共同将河口及三角洲综合统一规划做好。90年代广东省组织有关部门进行的珠江三角洲经济区规划就是一个良好的范例，但其范围希包括香港、澳门。希望国家有关部门，支持河口及三角洲综合规划科研和前期工作，安排必要经费，组织推动这对21世纪中国沿海经济发展将起重大作用。河口滩涂开发以及三角洲水利问题，应引起全社会关注和重视。按98年国务院批准的水利部三定方案，希水利部设立专门部门负责河口，抓规划、科研、及前期工作，并建立强有力的河口开发整治领导协调机构，并进行投资分摊和集资、引资政策研究。按新水法制定河口有关法规与细则，使河口开发整治纳入法制轨道。
Remarks on the ESTUARIES IN CHINA
YANG
Zhenhuai
(
November 2003, Hangzhou, China )
China mainland
coastline starts from Yalujiang River mouth in the north and ends to
Beilunkou in the border of China and Viet Nan, with a total length
of 18000 kilometers. It is 32000 kilometers in all if the island
coastline is included. The coast region covers an area of 350000
square kilometers, including a tidal region area of 100000 square
kilometers and a tidal flat area of 20000 square kilometers. The sea
areas are 157000 square kilometers within 0~20 meters deep,
including an area of 124000 square kilometers within 0~15 meters
deep, 63000 square kilometers within 0~10 meters and 27000 square
kilometers within 0~5 meters. China has a vast area of tidal flats
and possesses a broad potentiality of development. Mean runoff
amount into sea per year is 1724300 million cubic meters. Mean
sediment deposition into the sea a year is about 2000 million tons.
There are 1800
estuaries of varying sizes and different shapes in China, including
more than 60 estuaries with a river length of over 100 kilometers.
In addition, there still exist 160 bays in China. They have better
marine transportation ability and a definite sheltered condition.
Most of them have more stable deep water coastline and submarine
deep channel. The port resources has been early developed and
utilized, but river mouth bars exist in the harbor sites in estuary.
Improvement is needed for a better navigation. High tide levels for
some estuaries, such as the Yangtze Estuary with a mean tide range
of 2.67 meters, the Pearl River Estuary with a mean tide range of
1.69 meters and Haihe River Estuary with a tide range of 2.15
meters, can be use to raise the navigation ability.
Looking forward to
the 21th century, Japan has developed artificial islands, airports
and cities at the sea to open up the space of human needs. In the
future, airfields at the sea, submarine warehouses and undersea oil
and air tanks will be constructed. Following the building of
submarine tunnels and bridges on the sea, resources in many islands
are going to fully developed and utilized.
As an intersection
spot of rivers and coasts, estuary contains both flood and sediments
from rivers and threat of marine storm wave and saline-alkali
injury. But it is a crossing place of fresh water and salt water,
bringing us limitless life and rich nutrition, which has formed
manifold bio-resources such as crab and sea eel fry etc. and has
also become a migratory path for famous and precious fishes.
Sediment deposited year by year into the rivers is gradually making
the shallow sea become wetland and further forming land, lastly
turning into a lot of estuarine deltas in the world, which are a
good place for humanity to multiply. It is just sediment deposition
for several thousand years and building water conservancy projects
by the Chinese people of past ages to bring about 13 million
hectares fertile lands, with about 10 percent of China cultivated
lands, such as middle and lower reache plains of the Yangtze River,
the Pearl River delta, the Yellow River plain, the Huaihe River
plain , the Haihe River plain and the Liaohe River plain etc.
Humanity raises their ability to know estuaries and coasts with the
historical developing process. From a benefit of food and clothing
in agricultural society to harbor economy in modern society, the
importance of estuaries and coasts has been deeply recognized,
especially oil and gas resources near sea shore have been discovered
and developed for twenty years, together with the economy globalism,
foreign capital incoming and foreign trade development. So
recognition to estuary is not limited to itself. It should be judged
by the national economy interests, combining productive forces
distribution in China with policy of opening to the outside. Estuary
should be by no means separated from rivers, deltas and sea, as well
as social economy development, environment and ecology.
In near five years,
the regional plans for main rivers in China have been revised and
approved by the State Council. The regional planning of marine
performance has been also approved. But the comprehensive programmes
for the coastal belt in estuary and delta have not been ratified. It
is needed for us to organize the relating departments, such as water
conservancy, water transportation, fishery, national land, urban
building, marine, environment, forestry, tourism, oil and gas and
salt etc., to commonly formulate it.
Particularly the
following programmes are urgently needed to be made: the
comprehensive water conservancy planning for the Pearl River
estuarine delta, including Hang Kong and Macao; the comprehensive
water conservancy planning for the Yangtze River delta, including
the Yangtze River estuary, the Qiantang River estuary, Zhoushan
Islands, north bank of the Yangtze River estuary and tidal flats in
the north part of Jiangsu Province; the comprehensive water
conservancy planning for rounding Bohai Sea including Beijing,
Tianjin, Shanxi, the Yellow River estuary, Haihe, Luanhe and Liaohe.
For several thousand
years, the Chinese labouring people have created good experiences
developing the estuarine delta, for example: polders and river
networks in the Yangtze River delta, mulberry bases and fish ponds
of banana base in the Pearl River delta. These man-made and natural
wetlands rear several ten million people in China. But in recent
twenty years, a large scale human activities, such as flat and beach
reclamation, constructing sluices in harbors and estuaries, digging
sand and rock, coastal engineering construction, building oil and
gas platforms on the sea etc., have caused a serious impact on
environment and ecology. Now more reclaimed flats have not been
utilized fully for lack of fresh water and without water system. A
lot of mangrove trees have been disappeared in the south of China,
which occupied 50 thousand hectares in 1980s and now 20 thousand
hectares left only. A quarter of coasts in Hainan Islands was coral
reef and 80 percent have been destroyed to a certain degree. Owing
to short water resources, rivers in the north were cut off, causing
fisheries moving outside or disappearing as well as disappearance of
fish, shrimp and crab migration. All kinds of resources, covering
offshore and estuarine reclamation, seawater culture, shellfish in
tidal zones and fish, shrimp, crab and algae etc., are declining.
The reclamation and shrimp area culture have made the natural tidal
flat wetlands reduce near one half of the wetland. Offshore seawater
has been seriously polluted, especially for industrial and sanitary
wastewater of about 8000 million tons per year into the sea,
together with accidents of oil tankers. The seriously polluted
places are Bohai Sea, the Yangtze River estuary, the Pearl River
estuary, the Qiantang River estuary, Zhoushan Islands, Dalian Bay
and Jiaozhou Bay etc. Valuable seawater animals as whales, sea cows,
seals, marine turtles, sea horses and famous shellfish resources are
being gradually disappeared . At the same time, the estuaries of the
Yangtze River, the Pearl River and Haihe River deposit seriously.
Flood discharging and the water transportation are gravely impacted.
In particular, Bohai Sea, as an inland sea in China, with an area of
only 70 thousand square kilometers and a mean water depth of 20
meters, is needed to take emergency protective measures.
Views on this
question are:
1.
About the Pearl River delta.
The cities of
Guangzhou Province, Nanhai, Panyu and Shunde were short of water in
low water period and water was seriously polluted when flood,
typhoon and storm tide occurred in 1915 and 1994. Considering this
point, it is necessary to perfect the flood control and drainage
system for the cities and ten dykes of Xijiang and Beijiang rivers,
to construct Datengxia water project, to build a multipurpose water
system for the Pearl River region in combination with the building
Longtan Reservoir in Hongshuihe River, Baise Reservoir in Youjiang
River and the completed Feilaixia Reservoir in Beijiang River. On
the basis of this planning, Sixianjiao reach at the intersection of
Beijiang and Xijiang rivers will be improved and some water projects
are gong to be built to increase low water discharge for the river
networks such as Beijiang River downstream in the east of Sanshui
and Guangzhou. It will make a greater contribution to improve the
water environment of Guangzhou and Shunde. When fierce flood occurs
in Xijiang River, the Pearl River delta can be prevented from
floods. There exist eight mouths in the Pearl River, in which tidal
flats are being gradually deposited and regulation is needed to keep
flood and navigation pass free.
Except Hang Kong
and Guangzhou Huangpu harbors, there exist Yantian Harbor, and Aomao
Harbor in Dayu Bay in the east, Shekou harbors and Zhuhai Gaolan
harbors in the west, together with Panyu Nansha Harbor which will be
built in the near future. All harbors have formed a harbor group,
which surrounds the middle part and the east and west parts of the
Pearl River delta. The social economy in the Pearl River delta and
Hang Kong, Macao and Zhuhai will become further prosperous to the
accompaniment of building a western passage in Hang Kong and
Shenzhen, as well as Hang Kong, Macao and Zhuhai Bridges crossing
the Pearl River mouth.
2.
Combining planning of the Yangtze River estuary with the
Qiantang River estuary and a deep water harbor group in Zhoushan
Islands
At present, it is
necessary to improve the Yangtze River estuary. The project is not
only in relationship with Shanghai Harbor, but close relation with
the harbors and navigation along the main reaches of the Yangtze
River. The first stage training project of deep water channel for
the Yangtze River estuary has now been finished and the second stage
is being built. The deep water harbors in Dayangshan and
Xiaoyangshan of Shanghai are being constructed. There exist more
than 30 deep harbors which are suited to building wharves in
Zhoushan Islands. There exist rich tidal flat resources in the
Qiantang River estuary. A highway bridge from Zhapu to Cixi is gong
to be erected. Nanyangkou deep water harbor in Nantong and
underwater passage crossing the Yangtze River mouth from Shanghai to
Chongming Island have been built. In the near future, the Yangtze
River estuary and the Qiantang River estuary will become the largest
deep water harbor group in the world and it is also turned into a
door to the outside in the whole region of the Yangtze River.
To solve water
pollution of Taihu Lake, it is an important measure to transfer
water from the Yangtze River into Taihu Lake and quicken circulation
of water in Taihu Lake besides building effluent plants in cities
and towns rounding Taihu Lake and devoting major efforts to clean
trashes on the Lake. The projects of pumping Wangyu River into the
Lake and building sluices in reaches from Zhenjiang to Jiangyin have
been completed. It is suggested to study the scheme of transferring
the Yangtze River water through Guchenghu Lake, Dongba and Xuhe into
Taihu Lake. In low water period, part of runoff in Yangjiang River
and Qingge River can be transferred into Gucheng Lake, maintaining
water transportation passage free without Taihu Lake.
3. Rounding Behai Sea
area
These harbors, such
as new Tanggu Harbor in Tianjin, Qinghuangdao and Jingtang harbors
in the north and Huanghua Harbor in the south, have consisted of a
door of Beijing and Huabei district of China. Qingdao and Huludao
harbors consider Jinan and Shandong Province as an inland, and
Dalian, Bayuquan in Yingkou and Huludao harbors consider Liaoning,
Dongbei and eastern Neimenggu as an inland. So a harbor group which
is rounding Behai Sea has been come true.
Situated between
Bohai Bay and Laizhou Bay, the Yellow River estuary delta is
starting from Taoerhe River estuary in the north and ending in the
gap of branch vein in the south, with an area of about 6000 square
kilometers. Since the Yellow River forced Daqinghe River way into
Behai Sea in 1885, there were more than 50 breaches and channel
changes within the scope of existing delta. The larger changes was
10 times in all.
Owing to lack of
rainfall and little runoff, the Yellow River has often shut off
since 1970s. The land in the delta was seriously salified and it was
very difficult for men and livestock to get drinking water. So this
was a place of rare trace of human habilitation in history. After
Shengli Oilfield was exploited in the end of 1960s, embankments were
erected in the Yellow River estuary and reservoirs in plain were
also built, so the channel of the Yellow River is being gradually
stabilized. Since an old river channel was changed into the present
one in 1976, it is stabilized for 30 years. The first problem for
the Yellow River delta is to stabilize the river channel into the
sea as well as flood control and storm tide prevention. The second
is to construct reservoirs in plain to meet the need of fresh water.
The third is to carry out warping irrigation, well irrigation,
pumping salt water out and replacing fresh water, washing salt and
soil improvement. The forth is about communication of railways,
highways, sea harbors and airports etc. The above four problems are
related to conducting the basic installation construction which
should do our best to consider water projects as the centre. As to
developing soil and water resources in the delta, the most important
problem is to deal with water which is supplied from the Yellow
River. 7000 million square meters water has been allocated to
Shandong Province and Shangdong Province has divided 780 million
square meters from among the allocated water to Dongying City.
However, the actual diversion water volume from the estuarine area
in 1995 was 1400 million square meters, in which Dongying was 860
million square meters. Average 23.8 square kilometers of land have
been formed in a year by sediment deposition of the Yellow River.
There exist cultivated lands of 300 thousand hectares in the
estuarine area, occupying 37.8 percent, and alkaline lands of 172
thousand hectares. The key point is short of water resources and is
how to use sediment of the Yellow River and improve alkaline lands
by warping irrigation. In addition, there are tidal flats of 313
thousand hectares, including the natural protection zones of 153
thousand hectares. The delta is rich in natural resources such as
oil, gas, salt and bittern etc. and has greater potentialities to
develop papermaking, livestock farming, oil and salt industries and
seawater breeding in combination with flood diversion and warping
irrigation, digging wells, pumping salt water for fresh water, as
well as the southern water being transported to the north in the
future.
4. Erecting sluices
in the northern estuaries
Owing to the water
resources is deficient in Huabei Plain, tidal gates have been
erected in most estuaries. Sediment deposition outside the gates
occurs seriously. A typical case is given as follows. Tidal gates
were built in Haihe River estuary in 1958. They are almost closed
all the year round to store fresh water. Sediment is deposited
downstream the gates and the river bed in the estuary reach is being
gradually risen. Every year, sediment of more than 500 thousand
cubic meters needs to be dredged. Although Beitang estuary of a new
Yongding River (a floodway) , situated near Haihe River estuary, has
no gates to be built, the problem of marine sediment deposition in
the scope of flux and reflux reaches is also difficult to be solved
owing to no runoff into the sea all the year round. At present, the
feasibility investigation for building gates in estuary is being
carried out. Similar cases also happen in Liaohe estuary. After
tidal gates were built in the middle-minor estuaries, runoff was cut
off, making original receiving tide volume in estuaries to be
decreased, with serious deposition and channel blockage. Some
middle-minor scale harbors have lost their original functions and
even become abandoned harbors. To this universal problem, Haihe
Water Conservancy Committee has worked out a regulation planning for
Haihe, new Yongding River and Duliujian estuaries. A jetty, with 5
to 10 meters below sea level, will be built in the right channel of
Haihe estuary, paralleling with the jetty of the new Tanggu Harbor.
It will cut off the channel which marine sediment backs along
coast. It plans to maintain the floodway in estuaries in
combination with dredging navigation pass. Except flood periods,
runoff does not flow into the sea all the year round. So sediment in
estuaries should be washed away by scouring in flood periods.
In general, the
problem in estuaries is the first to work out a regulation planning
for the estuary delta area. The key points are flood control,
typhoon prevention, waterlogging control and salt resistance,
together with floodway and channel improvement and dredging to
ensure the channel unblocked. The second is to prevent rivers and
lakes from pollution, especially fresh water resources protection in
urban and rural areas near estuary and the prevention of water
pollution. Water pollution in estuary and near sea is primarily
present in land trashes from rivers and lakes. Wastewater from
cities and towns and livestock breeding, surface pollution in rural
areas and aquatic farming is also an important pollution source. It
is needed to attach great importance to water pollution prevention
of inland rivers in estuary delta. According to the water
environmental volume of estuary and inshore sea, river runoff, tidal
current and water self-purification capacity, the total amount of
receiving sewage will be firstly determined and then inferences are
drawn upstream to confine draining sewage amount in estuary and
middle-upper reaches of rivers within necessary limits and to
prevent water from pollution for each watershed. The third is to
protect the estuarine environment and natural resources against
pollution. Estuary is rich in biological resources. Tidal flats and
wetlands are good places of laying eggs and incubation for birds,
fish, crabs, shellfish and migratory living things. Once they are
damaged, a great impact will be produced on ecological environment
and should make efforts to protect them actively. The comprehensive
water planning for the estuary and the delta should be formulated by
means of cooperation with each other, with unified planning,
considering coordination benefit of all parts, carrying out
comprehensive protection and rational development. To this
situation, it is required for the National Planning Committee and
related departments, such as water conservancy, water
transportation, aquatic products, land management, urban building,
sea, agriculture and stock raising, environment, forestry, tourism,
oil and gas, salt, to give full cooperation to finishing the
comprehensive planning of estuary and delta. It was a good case that
Guangdong Province had organized some departments in 1990s to work
out the planning of an economical developing region in the Pearl
River delta. But the planning should cover the two districts of Hang
Kong and Macao. Related departments of the Nation should support the
scientific research and earlier stage work of the comprehensive
planning in estuary and delta areas. The State should provide the
requisite capital for this planning and popularize it actively,
which will exert a great influence on China coastal economic
development in twenty-one century. All society should pay close
attention to tidal flat development in estuary and water projects in
delta. Wish the Ministry of Water Resources to set up a special
department responsible for estuarine work, grasping planning,
scientific research and the earlier stage work. At the same time, a
powerful leading organization for regulation and development in
estuary should be formed and carries out the study on the policies
of investment share, collecting and importing funds. Regulation and
exploitation of estuary is brought into the legal orbit in the light
of related estuarine laws and detailed rules stipulated by the new
water law.
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