Conflict of water using resources under the impacts of Ba Lai sluice dam in Ben Tre province

The buiding of gaint Ba Lai sluice dam is an importantpart of the Bac Ben Tre Water Management Project. The dam construction operation in April 30th 2002 influencesall brackish ecosystems to fresh water ecosystem and also changes sea - river dynamic operations, four districts include: Binh Dai, Ba Tri, Giong Trom and Chau Thanh. Since then, the livelihood of local people has change to adapt to a new characteristic of ecosystem. There are three main agriculture activities: agricultural activities in fresh water ecosystem, aquaculture, pork producer. These economic activities not only affects on the water system in this area but also leads to the conflict of water using in this area. The main objective of the paper is to analyze the current state of conflict on the use of water in people's lives under the impact of the Ba Lai dam. An indepth interview techniques in combination with reference from previous data were were applied to study in 36 households and 8 local governmental staffs. The maxtrict analyse base on primary data were characterized such as: (i) the conflict between aquaculture and fresh water agriculture households, (ii) the conflict between aquaculture households, (iii) the conflict between pork producer and (vi) the conflict between households and local government.

The Influence of Flood Discharge to the Stability of River Morphology

Sedimentation has been an issue for a long periode of time. It affects the river morphology process which is constantly changing from time to time due to its sediment supply system. There are 2 main parameters that strongly affect the morphological process and those are discharge and sediment. When the movement of the sediment occur it will lead to degradation and agradation along the river that will affect the river morphology. Because of those processes, the river dynamic characteristic should be considered in structural design.In North Sulawesi, Tondano River has been known as one of the main river and it has a discharge all year around. With rapid land coverage change, dicharge may increase significantly and hence more sediment could be transported. Moreover, there are increase use of the river resources and more structures built along its sides that appeared to have induced more sediment in transport.This paper presented the corelation between discharge of various flow rates and the amount of sediment being transported at these rates along certain river segments. Slight changes on morphology of the river due to degradation and agradation processes at these segments were also displayed Analysis was carried out to evaluate agradation and degradation processes during various flow rate at the middle section of the Tondano River. Prior to this was the analysis of river discharge. This research has confirmed that indeed the sediment transport occurred at the observed river’s segments was due to the varied discharges. The transport therefore instigated the recurrent changes on the river’s morphology this may pose threats to the stability of river’s structures i.e. by means of scouring progression. Solutions suggested to overcome the problem includes: 1). Non-structural or structural reinforcement on the river bank; and 2). Sediment management to overcome the degradation and agradation processes.

The Contribution of Different Restored Habitats to Fish Diversity and Population Development in a Highly Modified River: A Case Study from the River Günz

Despite of structural deficits, highly modified water bodies (HMWB) contain remnant populations of endangered fish that have high conservation value. Restoration in HMWBs underlies different principles when compared to natural rivers because of impaired river dynamic processes. The objective herein was to assess the contribution of restored habitats of the River Günz, Germany to fish diversity and restoration success of target species. All habitat restoration types, including bank habitats, fast flowing habitats with gravel, structured shallow water zones, nature like fish passes, and a former river course below a spillway were assessed. None of them comprised the full set of 27 fish species or size classes, indicating that the diversity and interlinkage of the restored habitats is most crucial to sustainable fish populations and high biodiversity. When considering the rheophilic target species Chondrostoma nasus and Barbus barbus, only fish passes and the former river course with their high flow current contributed much to their population development, particularly to young specimens <20 cm. The results of this study indicate that measures inside the main channel are unlikely to mitigate deficiencies in HMWBs concerning specialized riverine fish. Instead, interlinkage of a diversity of restoration measures and investment of resources for restoration in HMWBs into nature-like fish passes or former river courses below spillways with dynamically managed discharges seem most useful.

Carbon Reservoir Effects in Eastern Oyster from Apalachicola Bay, USA

Eastern oyster (Crassostrea virginica) is an ubiquitous estuarine shellfish taxon in eastern North America and one of the most abundant materials available for radiocarbon (14C) dating. We examine spatiotemporal variability in carbon reservoir effects among pre-bomb oysters from Apalachicola Bay, USA, a river-influenced estuary on the northern Gulf of Mexico. Shells were sampled at multiple points along the valve to produce time-series records of 14C variation during the lives of the mollusks. Conventional ages within shells differed by as little as 36 14C yr to as much as 295 14C yr. Reservoir offsets varied sub-regionally within the estuary, increasing from 92±37 yr in the eastern edge of study region to 227±110 yr in the west, reflecting the influence of 14C-depleted dissolved inorganic carbon from the Apalachicola River. Dynamic carbon reservoirs can pose problems for the estimation of ΔR and for building coastal chronologies. Estimating sub-regional ΔR values can be useful for assessing the range of variability in reservoir offsets within an estuary, and for correcting sample ages if the shell origin is known. Greater variability and/or uncertainty in ΔR lead to greater uncertainty in the calibrated age.