Abstract:According to the abundant data collected in field and laboratory experiments by the State Collaboration Research Group on Evaporation and Heat Loss from Water Surface since 1976 and a number of historical data observed in hydrological stations in the typical regions in China, the elements influencing evaporation from water surface and the nonlinear interactions between them are determined, new non-diiDensional parameters (w_e、Pv、Pe) and new structure of the formulae are recommended.The constant coefficients in the formulae are determined based on the statistical analysis on measured data.The formulae for calculating daily evaporation and heat loss coefficient from water surface by using the data of regular hydrometeorlogical elements (water temperature;air temperature, vapour pressure;wind speed and atmospheric pressure) have been ubtained.The formulae were tested by I860 group data cullected from buth natural lakes (reservoirs) and thermal polluted water bodies during various seasons in different climace regions of China, and from laboratory experimental data as well.It is shown then the accuracy of these suggested formulae is higher then that of other existing formulae. The paper cuasists of two parts.This is the first part, which includes the main nun-diiiiensional parameters influencing the evaporation from water surface, revision of sensible heat flux and atmospheric saturation state un evaporation, structure of the formulae and their empirical constants.

Abstract:Dongting Lake, situated in the south of the middle reaches of the Changjiang River, is the second largest freshwater lake in China.According to the properties of sediments in Holocene and ancient cultural relics in various periods, as well as pollen data and historical records, the evolution of Dongting Lake can be divided into six stages. From later Pleistocene to early Holocene, Dongting Lake area was an alluvial plain with several small lakes and incised rivers since the level of the Changjiang River was 20-40 m lower than that of the present.During 8000-5000 a B.P., with the rise of the water level in the Changjiang River resulted from high sea level, as well as Wcirm palaeoclimate and plentiful rainfall, the water of four inlet rivers was jammed into this area to turn Dongting Lake into a large lake,an area starting from the Yuanjiang River mouth to Yueyang with a width trf 17-33 km.During 5000-3000 a B.P., the former large lake was divided by the fouMiver compound delta into several small lakes auid swamps due to dry palaeoclimate.During 3000-1700 a B.P., more than five large lakes and many swamps were formed in the lowland.From 1700 a B.P.to the 19th century, with the formation of Taiping Breach and Ouchi Breach relevant to the burst bank of the Changjiang River, and plentiful precipitation, Dongting Lake reached its largest area of 6000 km².Beginning from the middle of the 19th century, as 0.984×10⁸m³/a of silts carried in by the Changjiang River and four inlet rivers and a large-scaled reclaimed land from lake, Dongting Lake decreased rapidly to 2691 km² in the 1980s.

Abstract:On the basis of comprehensive research on the information of geology, geomorphology, channel hydrography, meteorology, historical documents and archaeology of Yunmeng Marsh and Jingjiang Delta, some conclusions are obtained as follows: (1) The Yunmeng Marsh was formed at the end of late pleistocene ice age, when the sea level was declining draniatically resulting in the cutdown of the river-bed of the Changjiang River.As the climate went warmer in the postglacial stage, the gradual rise of sea ievel made the gradient of the Changjiang River more gentle, the sedinientation against the stream took place and the river level began to rise.When the flood breached the bank after the original channel was mandated, the Yunmeng Marsh was formed in the Jingjiang River (middle reach of the Changjiang River) area.The early marsh limited mainly in the abandoned river valley, when constant deposits in the Changjiang River accumulated 0n the lower lands, the marsh was enlarged.The marsh was vast with lands and shallow water interlocked, including the areas of Changjiang River, Hanshui River and part of the Dong ring Lake, (2) The Jingjiang Delta experienced three changes in history;the delta was a part of the developing Yunmeng marsh till Tang and Song dynasties;of the developing Jingjiang bend plain till the end of Qing Dynasty;of the developing Dong ting.Lake delta since the early 19th century.It was concluded that the migration of the Jingjiang Delta showed sume gradient southward.(3) The evolution of the Jingjiang Delta has proved some characteristics of stages.The early delta was thin due to plane accretion on a big area.while later vertical accretion along the diversion channels increased its thick ness.The depocemer position of sediments was the main factor affecting the delta's evolution.urhers were the neutectonic muvement and human activities such as dike building, etc.(1) The developmein and migraduii of Jingjiang Delta in history led Co the dramacic rising of flood level in Dungting Lake and Jianghan plains.Beginning from Pleistocene, the first rising period was from pustglacier age tu some 5000 years ago while the second in the late Ming or early Qing dynasties. Nowadays because of many discharge diversions of the Changjiang River, a great quantity of sediniems depusited to the south of Dungting Lake,the lake bed rose ajid the surface area shrank gradually.Were some programs and counter-measures not employed.the third rising period of fluucl level would Come to reality in no time,which would make the flood control of the two lake plains more difficult to deal with.

Abstract:Hydrological data from 1951 to 1988 show that the average runoff of Dongting Lake was 3019×10⁸m³/a, of which 54.6% came from four inlet rivers (Xiangjiang River, Zishui River.Y uanjiang River and Lishui River), 37.1% from three diversion waterways (Ouchi Waterway, Songzi Waterway and Hudu Waterway) of the Jingjiang River and the rest 8.3% from other sources.The average sediment load transported into Donating Lake was 193×10⁶ t/a, of which 82.3% came from three diversion waterways and 17.7% from four inlet rivers.From 1951-1958 to 1981-Ui88, the runoff volume and sediment load of Dongting Lake were decreased by 29.2% and 48.7% respectively as a result of the follows: (I) the depusition of three diversion waterways of the Jingjiang River;(2) curve cut-off in the lower reaches of the Jingjiang River.The decreases in runoff and sediment of Dongting Lake have favorable effects un the flood control at Dongting Lake, Jianghan Plain and the middle reaches of the Changjiang River.

Abstract:The under-ice fibro-vascular plants have been observed to be survival in the winter beneath some water bodies in three northern provinces of China (Jiling, Liaoning and Inner Mongonia), including Potamogeton crispus, Mpriopyllum spicalum, Potemogelon maeckianus, Ceratophyllum detnersum, Bairackium bungei etc.The biomass of these plants varies from 10 to 3500 g/m²,while their fresh weights in a unit area are in such order as Potflmoyeton cripus, Myriophyllum spicaium, Polamogeion maackianus, Ceratophyllum detnersum and Batrachium bungei. According to the outcomes of black-white bottle tests, the amount of oxygen produced by these plants through photosynthesis fluctuates between 0.039 and 3.610 mg O₂/d·g (plant), in which the Polamageton crispus gives the biggest, others are Batrachtum bungei, Myriophyltum spicatum, Ceratophyllum demersum accordingly.

Abstract:The standing crop of plankton and primary productivty of phytoplankton are surveyed in Sandaohe Reservoir, Hubei Province from April to October, 1990, The results show that there are 39 genera of phytoplankton, subordinate to 8 phyla, and 37 genera of Zooplankton, of which Protozoa, Rotifera, Cladocera and Copepoda account for 12, 13, 7 and 5 species respectively.The gross primary productivity of phytoplankton in the water column reaches 3.950 g O₂/m²·d in average in the period of April to October, 1990.The mean standing crop for phytoplankton and zooplankton is separately 1139 ind./mL, 2.085 mg/L and 1253 ind./L, 1.327 mg/L.The potential annual production of silver and bighead carps may raech to 15×10⁴ kg.The number of silver and bighead carps fingerlings (5 cm in length) to be stocked each year should be 78×10⁴ and 143×10⁴ respectively.

Abstract:The present paper deals with the age compositions, growth rates,condition coefficients, recapture rates, productive results and economic benefits of principal aquatic products which were stocked artificially during 1986-1988 in Gehu Lake. The recapture rates of black carp (Mylopharyngodon pureua), grass carp (Ctenopharyngod on ulellus) and blunt snout bream (Megalobrama amblycephala) were 23.85%~39-88%, silver carp (Hypophihaimichthys moliirix) and bighead carp (Aridvchthya nohilig) were 8.20%-19.63%. megalopa of mitten crab (Eriocheir avienaiti) was 2.69%. young mitten crab was-18.57%. The average production results of fish stocking increased by a factor of 14.3 and the average economic benefits by a factor of 9.6.

Abstract:According to the thesis of fuzzy hydrology that there exists no definite limits between clean and polluted waters but fuzzy characteristics in the process of the recognition, the authors present the following fuzzy mathematic model of lake water environmental assessment and rank:??? The model is applied to the rank of the eutrophication situations for J2 lakes in China* and the results are in agreement with the facts.Moreover,the model is suitable to the assessments in other environmental fields.

Abstract:According to the law of "Prevention and control of water pollution" and requisitions of emission licence system of water pollutants, combined with the realities of local water pollution In lake? the technical principle, work programme and calculation methods for water pollutant emission standards are put forward, i.e.(I) for uniformly mixed lakes, and (I) for nonun iformly mixed lakes.Some calculated examples in some typical lakes are further given for local lake management departments in making pollutant emission standards.

Abstract:Integrated fish culture in reservoirs, which combines cultured fine feed-eating fishes in net-cage with stocked feed-fiJter fishes out of net-cage in a ratk,nal proportion, is introduced-In teg rated fish culture is based upon environmental capacity criteria so as to take centre in feeding net-cage fish culture, to explore avenues by rationally using fertilizer to fish stocking and to increase output and effect.Furthermore, it can promote nutrient transference and enhance the energy conversion efficiency.As a result,the aquatic ecological conditions of reservoirs can be improved,the nutrients of ecosystem be transferred into fish production through various channels, the economic and eco-social ben if its of the ecosystem be obtained optimally. To carry out intergrated fish culture in reservoirs, the natural conditions, practical fundamentals and theoretical basis are described.The structures of ecosystem and interrelations between them in integrated fish culture are further analysed.The capacity of feeding net-cage fish culture is calculated and the ratio of stocking feed-filter fishes out of net-cage also recommended.Furthermore, the potential fish productivity for integrated fish culture in reserviors is predicted as follows: the total output can reach up to 3015.0 kg/ha, 6.7 times as much as that of extensive culture, and 3.4 times as that of fertilizer-used fish culture. The suggested integrated fish culture in reservoirs can be regarded as a reform favorable for traditional production system of fish culture in China, and a new stage in the process of turning extensive stocking into ecological flshery.

Abstract:Based upon the monthly,obtained data on water quality from 1981 to 1990 in Poyang Lake district, the status quo and trend of water quality in Poyang Lake are comprehensively analysed.The results are: (1) BOD₅ surpluses by 2.1%~22.2% in 1990 in some inlets and near some stations of the lake area;TP surpluses by 9.1%-29.3% at all stations except the esturies of the Gangjicing Rever (West Branch) and Fuhe River;(2) As,volatile phenol and TP are the main pollutants;(3) the natural conditions of the lake are not favorable for eutrophication though TP and TN exceed the limit in some areas;(4) the general assessment results show that water in the inlets of the Xinjiang River (west Branch) and Banghu and in lake areas such as Sheshan, Duchang, Zhuxihe River mouths belongs to type B, while that of the other areas belongs to type II;(5) the contents of As, COD, NH₃-N, DO and BODs fluctuate from year to year, while As and COD have been inclined to an increase since 1986;(6) with the increasing inlake pollutants, the water will be aggravated gradually.