Wuli Lake Research Articles

On the Integrated Control of Water Environment of Wuli Lake? Lake Taihu

在分析太湖五里湖水环境现状和污染成因的基础上,提出生态清淤、污水截流、退渔还湖、动力换水、生态修复、护岸整治等一系列水环境综合整治工程措施,并分析各项工程实施对污染物去除量的估算,预测对五里湖水质改善的影响和效果,进行五里湖、梅梁湖水环境综合治理的探索,为全太湖和其他湖泊水环境综合治理提供科学依据.;Based on the analysis of the actual environmental state and causes of the pollution of Meiliang Bay and Wuli Lake in Lake Taihu, this paper proposes several control measures to improve water ambient quality of Lake Taihu area, which are ecological mud removal, give-back fishing to lake, dynamic water exchange, ecological restoration and retaining wall repair.Moreover, it analyzes and predicts the effect on water ambient quality of the application of these engineering projects.So, this paper explores the integral control measures of Wuli Lake and Meiliang Bay in order to meet the needs for the control of whole Lake Taihu and other lakes with some scientific support.

Acid Volatile Sulfides and Simmltaneous Extracted Metals in the Surficial Sediments of Wuli Lake, Lake Taihu

Acid volatile sulfides(AVS)in surficial sediments from Wuli lake,Lake Taihu,2002are available for binding with divalent cationic metals through the formation of insoluble metal-sulfide complexes,thereby controlling the metal bioavailability and subsequent toxicity to benthic biocommunities.AVS concentrations and simultaneous extracted metals(SEM)values are determined have become the major research topic asso-ciated with sediments.The ratio of SEM to AVS is promising to predict metal toxicity.From investigated AVS and SEM during summer and autumn at five locations of Lake Taihu,it was found that SEM-AVS values and AVS concentrations did vary significantly between locations during both seasons.AVS concentra-tions were greater during summer than spring;SEM concentrations did not significantly vary between seasons at the same location,which resulting in significantly lower SEM-AVS values in summer.SEM-AVS values were greater than one at each location during both seasons illustrated there might exist heavy metals toxicity in Lake Taihu sediments.

On the adaptiveness of aquatic macrophyte to the sediment in Wuli Lake

在五里湖富营养化过程中,氮、磷及有机物质在湖底沉积物中大量积累。在夏季高温、高水位期。底泥中因有机物分解耗氧强烈和溶解氧补给受阻而发生缺氧。挺水植物和浮叶植物均能适应这种底质条件;在水温低于30℃或水深小于1m的情况下,五里湖的底质条件对沉水植物生长十分有利;但在夏季,当水温超过30℃且水深远大于1m时,底泥和底层湖水中的厌氧环境会引起沉水植物烂根,故沉水植物无法在五里湖渡过夏季,成为重建水生植被的障碍。适当降低水位,开挖湖心区底泥,在沿岸带堆积造成人工浅滩,可以创造出适合水生植物生长的生境条件。;In the eutrophication process of Wuli Lake, large amount of nitrogen, phosphorous and organic matter accumulated in the sediment of the lake bottom. In summer, oxygen deficiency often occurred in the sediment and bottom water, because high temperature enhanced biochemical oxygen consumption in the sediment and water, but the high water level greatly limited oxygen supply of the bottom water and sediment. The sediment condition was suitable for emerged plant and floating-leaved plant all the time, and even favorite to submerged plant when the temperature was below 30℃ or the water depth was less than 1m. In summer season when the temperature was over 30℃ and the water depth was beyond 1m, the anaerobic condition in the sediment and bottom water could destroy the root of submerged plant and cause it floating-up. It became an obstacle for restore aquatic vegetation in Wuli Lake that submerged plant could not survive the summer. To create suitable habitat for aquatic plant in Wuli Lake, the water level should be controlled, and the fertile sediment in the center of the lake be moved to the littoral zone to make it more shallow.

Ecological restoration of shallow, eutrophic lakes-experimental studies on the recovery of aquatic vegetation in Wuli Lake

依据浅型湖泊生态系统的多稳定态理论,在富营养湖泊治理过程中,当外来污染得到有效控制时,通过人工重建水生植被可以加速湖泊的生态恢复。在五里湖中,挺水植物和浮叶植物都能很好地生长,水底光照不足是沉水植物难以生长的主要原因。在自然条件下建成了永久性挺水植物群落和浮叶植物群落,在人工控制的围隔环境中改善了水底光照条件,建成了沉水植物群落。但这些沉水植物仍不能渡过夏季,主要原因是湖水过深和水温较高,降低水位和建造人工浅滩可为五里湖沉水植被恢复创造有利条件。本研究可为富营养水体的水质控制和植被恢复提供多种实用技术,但在水生植被的结构与环境功能等方面仍需开展深入的定量研究。;According to the theory of multiple stable states of shallow lake ecosystems, it is possible to speed the ecological restoration process by recovering aquatic vegetation in eutrophic lakes. In Wuli Lake, both emerged plant and floating-leaved plant could adapt to the eutrophic habitat, but submerged plant was limited by low light intensity at the lake bottom. Permanent e-merged plant community and floating-leaved plant community was built under natural conditions of Wuli Lake, and some submerged plant communities were set up in the enclosures where the water quality was improved and the underwater light intensity increased. The submerged plant community could not survive the summer for the high water temperature and high water level in the season. To make the habitat in Wuli Lake suitable to submerged plants one possible way is to control the water level and build shallow littoral zone by moving the fertile mud from the center area to the littoral zone. In the present studies, some usable techniques have been mastered for water quality control and aquatic vegetation recovery in shallow eutrophic lakes, and more detailed quantitative studies were needed on the relationship of structure and environmental function of aquatic vegetation.

Effects of environmental factors on release of phosphorus from sediments in Wuli Lake

本文论述了溶解氧、pH、温度和沉积物中微生物作用对太湖五里湖区沉积物磷释放的影响,以及在pH为8.4、好氧和厌氧二种状态下沉积物释放试验后滤液对斜生栅列藻(Scende smas obliqaas)和羊角月芽藻(Selenastram caprivarnnlam)增长的影响.结果表明:溶解氧降低、pH和温度升高、微生物作用有利于沉积物磷向水体释放,与湖水组相比,厌氧状态下沉积物磷释放后滤液能显著促进斜生栅列藻增长,但不能促进羊角月芽藻增长,好氧状态下沉积物磷释放后滤液均不能促进二种藻类的增长。;This paper studies the effects of DO, pH, temperature and the growth of bacteria on the release of phosphorus from Wuli Lake sediment.The result of experiments shows that the quantity of phosphours released from sediments into the water body was getting greater with decrease in DO, pH, temperature but increase in the growth of bacteria.The filtrate of the anaerobic release test may stimulate the growth of Scendestnus obliquus, but not the growth of Selenaslrum capricornutum.It is showed that filtrate of the aerobic release test can stimulate neither of the algae.

Studies on eutrophication of Wuli Lake and possible restoration strategies

1990-1991年对五里湖的调查表明,该湖已发展到富营养一重富营养阶段。湖水中TN、TP、Chla、BOD₅和COD_cr的平均含量分别达到2.25mg/L、111μg/L、31.8μg/L、4.9mg/L和17.5mg/L,平均透明度只有0.51 m。表层底泥中氮、磷和有机质的含量分别高达0.181%,0.071%和2.51%,成为巨大的内营养源;而外源营养物则主要来自梁溪河和五里湖北岸各支流。以硅藻为主的浮游藻类年生产力约为5200 t/km²(鲜藻),是该湖有机污染的主要来源。治理应从污染源控制入手,在东北端河道上建闸拦污,在北岸建立环湖集污河道;废止航运和局部清淤以削减内污染源;在沿岸带恢复水生植被以固持底泥;在东部湖区建立拥有水生植被的水源保护区以改善中桥水厂的水源水质。;According to the surveys from 1990 to 1991, the Wuli Lake entered a eutrophic period, which seriously affected drinking water supply and entertainment.The mean concentration of TN, TP, Chla, BOD and COD in the lake water were 2.25 mg/L, 111μg/L, 31.8 μg/L, 4.9 mg O₂/L and 17.5 mg O₂/L respectively.The water had a mean SD of only 0.51 m.The mud in the bottom contained 0.18% of nitrogen, 0.071% of phosphorous and 2.51% of organic matter.The phytoplankton dominated by diatom gave an annual productivity of 52 t/hm² (fresh algae), the main source of organic matter in the lake.To restore this lake,the pollutant input should be cut off by building sluice gates on its rivers and setting up waste water dispersing system around the lake.The mud should be removed from the lake bottom and water transport forbidden.Re-establishing aquatic vegetation in the Littoral zone would effectively promote the restoration of water quality and environment.It may be a good way to improve the drinking water quality in a short time by setting up a water source protective area in the eastern part of the lake and recovering aquatic vegetation in it.

Pen culture in Wuli Lake, Jiangsu, China

Two trials were run in which small fingerlings of Chinese carps and tilapia were reared to marketable-sized fishes in one year. The pen was made of single-layer polyethylene nets without nodes. In 1985, the pen area was 4.8 mu (15 mu = 1 ha) and the average yield was 305.75 kg/mu with a marketing rate of 98.7%. In 1986, the area was 4.5 mu and the average yield was 793.5 kg/mu with a marketing rate of 90.23%.