排序方式: 共有12条查询结果,搜索用时 44 毫秒
1.
2.
According to the social and natural conditions of Taihu Lake Basin, the planning objectives and some ideas for water pollution prevention in Taihu Lake and its surrounding river-lake system are proposed. 相似文献
3.
4.
克里雅河流域生态环境变化与水资源合理利用 总被引:3,自引:2,他引:1
水是极端干旱区重要的环境资源。由于自然因素的影响,克里雅河历史时期的沙漠化过程表现为水文网系缩短,天然绿洲沦为沙漠;现代环境变化主要由人类经济活动引起,一方面于田绿洲面积扩大,生产发展。另一方面人类不得当的干涉,造成了环境的不利变化,特别是对下游天然绿洲。以流域为单元的国土整治,合理开发利用水资源是确保生态环境稳定的基础。大河沿天然绿洲在探索干旱区环境变化和植物演替中,有特殊意义的自然景观地域,拟建为自然保护区,每年确保1.0-1.5亿m3水量是必需的和可行的。于田绿洲发展与保护区建立是相辅相成的,共寓于统一的流域生态系统之中,搞好土地生态规划,建立合理的农林牧生态结构和布局,搞好流域土地生态系统功能管理,以期取得良好经济效益和生态效益。 相似文献
5.
水在克里雅河流域生态地理环境中的作用 总被引:2,自引:0,他引:2
水是克里雅河流域生态地理环境的主导因素, 依水系分布形成的于田绿洲和天然绿洲共同构成了克里雅河流域生态系统。克里雅河为混合引给型河流, 冰川融雪补给占71%, 故径流年内变化大, 年际变化比较稳定, Cv=0.17。地下水天然补给量大部是地表水转化而来。水资源开发利用中, 既要分析上游绿洲开发对下游的影响, 又要考虑维护下游天然绿洲对上游人工绿洲开发的制约, 统筹兼顾。北部深入塔克拉玛干沙漠200多公里, 沿河阶地, 河漫滩及散流区宽5-10km的天然绿洲, 是保护于田绿洲稳定的前沿屏障, 有重要的社会生态意义。目前因水系变迁和洪水退缩, 植被衰败, 沙漠化过程发展。从环境、资源生态管理和保护出发, 宜建立克里雅河下游天然绿洲保护区, 确保下游干三角洲天然绿洲的稳定。天然植被的维护更殖再生, 应纳入整个流域水资源生态系统的总体管理之中。 相似文献
6.
The eutrophication of Lake Taihu is becoming more serious day by day and more urgent to be comprehensively harnessed. The lake sludge is considered as a important polluting factor. To control the internal pollution source of Lake Taihu and restore its water ecological environment, this paper put forward an idea of the dredging for environmental purposes. It was on the basis of the research on the sludge storage and physical/chemical characteristics. The technical keys are sludge-dredging depth, time, method and sludge treatment. The requirements and scheme for the environmental dredging work in Lake Taihu were also analyzed in detail. 相似文献
7.
西北干旱地区,占全国土地面积的30.8%,气候干旱,降水稀少,地面组成物质疏松,风沙活动频繁。高山和盆地相间的地形及垂直地带性结构,形成丰富多样的自然资源和复杂的自然条件。区内多年平均降水不超过250毫米,西部平原多在150毫米以下,还有多年无雨之地;但山区降水丰富,冰川发育,是地表径流重要补给来源。水是西北地区一切生物生产和人类经济活动的主要制约因素,它既是自然资源,也是环 相似文献
8.
太湖富营养化问题及其综合控制对策 总被引:1,自引:1,他引:0
On the basis of nine-time current situation investigation for eutrophication of Taihu Lake during 1991-1995, this paper evaluated the trophic levels in the different periods and analyzed the development of the main nutrient content in the nearest 35 years. The results show that the trophic level of Taihu Lake is in the transition state from meso-eutrophic to eutrophic. The eutrophhic and hypereutrophic waters account for 10% or so. The limiting nutrient, P, rises most rapidly, which causes the ratio of N:P to decrease. The increase of P content is still one of the main factors giving rise to the eutrophication of Taihu. LakeSome proposals of comprehensive countermeasure for the eutrophication are put forward. They include the pollution source control of the basin, the littoral multiple management, optimal dispatch of water conservancy facilities, the engineering of helping Taihu Lake with diversion of the Changjiang River, and as well as the setting of the water quality protection and legal system. 相似文献
9.
The water pollution situation of Taihu Lake, general conditions of the main inflow rivers to Taihu Lake, the compiling principles, the harnessing measures for polluted water and major inflow rivers to the lake, and the total quantity control plan were analyzed. 相似文献
10.
腾格里沙漠沙坡头地区植物生长与水分平衡的初步研究 总被引:25,自引:8,他引:17
沙坡头地区降水是水份的主要补给来源,占补给总量的98.3%;凝结水仅对一年生短命植物有作用,无明显实际意义,尤其对灌木和半灌木。沙地蒸发散量是主要的消耗项,其占年降水的89.7—112.8%,有负亏缺现象,特别是固沙年代较长地区,人工防护体系发生变化和演替,水分不足是主要原因。热量变化是沙地水分运动的主要动力条件,容积热容量、导热系数、热扩散量是沙地热力学运动的基础参数,它与土壤水分和干容重相互制约,壤中热流和壤中水流耦合运动研究将进一步揭示水分运动规律的实质。 相似文献