河口湿地围填造地的适宜性和资源环境问题——以福建三沙湾湾顶河口区为例

以福建宁德三沙湾内鲈门港湾顶霍童溪和七都溪入海口之间的潮滩(实际为潮汐汊道)围填为例,从工程地质、水文条件、生态环境等方面探讨其围填造地的适宜性,并应用数值模型、潮汐汊道理论以及生态学原理预测其对区域资源环境的影响.具体为:河口围填后相当于河流近口段、河口段、口外海滨段相应地向海延伸,必然会引起河口体系的自动调整并形成新的动态平衡;在这种自动调整过程中,所在区域的资源环境会受到一系列的影响,包括河口地形地貌改变而导致径流和潮流动力条件变化进而引起滩槽冲淤变化、河流入海流路变化而导致流域排洪在一定程度上受阻、河流入海流路冲刷对跨海大桥桥墩或其它构筑物稳定性的影响、湿地占用导致底栖生物破坏和生物生境缩小进而导致生物群落改变和渔业资源受损、以及河口景观改变等.建议河口潮滩湿地围填应综合考虑河口的水文条件、防洪措施、环境容量以及围填后河口体系的自动调整作用范围、维护岸滩和已建构筑物稳定以及维持航道水深的工程量和成本、围填护岸形态结构与生态环境的相适宜程度等,并综合权衡损益.

Reclamation at Estuarine Wetland and Its Impact on Resource and Environment——A Case Study of Sansha Bay, Fujian Province

Taking the reclamation of estuarine area(tidal inlet)between Huotong River and Qidu River in Sansha Bay of Fujian as an example,reclamation adaptability of engineering geology,meteorology,hydrology,and entironment was analyzed,and its impact on resource and environment was predicted by numerial model,theory of tidal inlets,and theory of ecology.After reclamation,the mouth of river extends towards sea,causing the system of estuary adjustment automatically and reaching a new balance.Its impact on resource and environment around estuary include:dynamical environment of runoff and tide current transform because of topographic and geomorphologic change,silt-scour of beach and channel transfer because of dynamical environment change,drainage clag because of runoff altering,community shifting and fishery resource decreasing because of wetland being encroached and biologic environment shrink,landscape remodel because of contrived action.Some suggestions of reclamation at estuarine wetland,such as hydraulic condition,infrastructure of flood-prevention,environment capacity,the scope of estuarine system auto-readjustment,cost of keeping coast and building in stable,and compatibility between configuration of reclamation and environment,are present.