MANAGEMENT OF KUIN RIVER USING THE ECO-HYDRAULIC APPROACH

River management using the eco-hydraulic approach is aimed at preserving the ecological components in the river environment through hydraulic engineering. This study aims to identify the existing conditions on Kuin River border, analyze the relationship and influence of community activities on the banks of Kuin River on the water quality of Kuin River, and study the river development pattern with the concept of eco-hydraulic on Kuin River. Data were collected based on the results of field surveys and laboratory tests for water and soil. The results showed that the current condition of the riverbank of Kuin River has not fulfilled its function as a buffer space between the river and the mainland, due to the large number of community settlements rather than vegetation that functions to protect the river. Kuin River is polluted because several ecological indicators such as pH, Fe, BOD, and COD have exceeded the maximum allowable limits. This occurs due to social activities and development along the river, which have an impact on biotic and abiotic aspects of the river. The type of soil on the banks of the Kuin River is silt mixed with clay with moderate to high plasticity. Based on this condition, there is an assumption that the cliffs on the banks of Kuin River have the potential for landslides. Therefore, a pattern for developing cliff protection using riverbank vegetation components is recommended

The role of increasing riverbank vegetation density on flow dynamics across an asymmetrical channel

Over the last two decades, the role of vegetation in the environmental and ecological restoration of surface water bodies has received much attention. In this context, the momentum exchange between the flow through the main channel and the riparian zone is a key mechanism. The primary goal of this study is to investigate the role of bank vegetation density on flow dynamics across the whole channel. This experimental study presents the major findings from a series of flow measurements across a channel having a sloping bank with vegetation at varying densities. The experiments are conducted under the same, uniform flow and fixed bed conditions, for a range of six linear and rectilinear arrangements of incremental streambank vegetation densities. A set of ten velocity profiles is obtained across the test cross-section of the channel, including the riverbank, for each vegetation density. These flow measurements are analyzed to derive roughness coefficients, which are related to the bulk flow velocities through the main channel and the riverbank and discuss the redistribution of flow velocities. An approximate doubling for the estimates of time-averaged boundary shear stress at the main channel, is observed for the case of no to dense vegetation, which enable further discussing implications for the stability of bed surface material. It is found that the vegetation arrangement, in addition to vegetation density, can have a strong impact in modifying the mean flow velocity at the main channel, for low riparian densities (φ < 0.6%). Highlights Flow dynamics are measured across the whole channel, including the vegetated riverbank. As stem density increases, mean flow velocity in the main channel increases while mean flow at the riverbank decreases. The arrangement of riparian vegetation can be as important as that of the density, in modifying the mean flow field of the main channel, for low riparian densities. Bed shear stresses at the main channel are estimated to increase with riverbank vegetation, reducing the stability of the stream’s bed surface.

Short Communication: The composition of undergrowth vegetation in the Gendol Riverbank, Sleman District, Yogyakarta, Indonesia

Syahbudin A, Meinata A, Arifriana R, Wiyono. 2020. The composition of undergrowth vegetation in the Gendol Riverbank, Sleman District, Yogyakarta, Indonesia. Biodiversitas 21: 1786-1792. Gendol river is one of the rivers affected by a pyroclastic blast from Mount Merapi eruption in 2010. This river flows through several villages, such as Glagaharjo, Kepuharjo, Wukirsari, and Argomulyo. On this riverbank, vegetation has grown naturally post-eruption of Mount Merapi and is continues to change. Some vegetation was also planted by the community. This study aims to find out the composition of the undergrowth vegetation on the Gendol riverbank in Cangkringan Sub-district. The data was obtained systematically by marking 10 sample plots of 5 m x 5 m and 2 m x 2 m size, on each side of the bank. A total of 68 species were recorded in this study which consisted of 29 trees species in seedlings and saplings stage, 34 species of herbs and shrubs, and 6 species of grasses. The dominant among the non-tree species are Chromolaena odorata (L.) R.M.King & H.Rob. with an IVI of 43.78%, Alternanthera brasiliana (L.) Kuntze with IVI of 16.6% and Asystasia gangetica (L.) T. Anderson with IVI of 15.78%. Saplings are dominated by Falcataria moluccana (Miq.) Barneby & J.W. Grimes with IVI of 32.81%, followed by Leucaena leucocephala (Lam.) De Wit (IVI-24.41%) and Melia azedarach (IVI-14.28%).

DPSIR Framework – A Decision – Making Tool for Municipalities

Many municipalities in Central Europe deal with the problem of invasive species in their natural ecosystems. Invasive vegetation eradicates native species and causes dense stands that damage the natural environment. This work shows how important it is to have an informative tool for municipalities to be successful in their struggles with invasive species. A Driver – Pressure – State – Impact - Response (DPSIR) framework is a decision - making tool, and this one is particularly applied to the species Fallopia japonica. Fallopia japonica is an extremely invasive and aggressive weed, and it is very often found in riverbank vegetation. This specific framework can be used as a tool for municipal managers to highlight all the problems with Fallopia japonica and define all the responses that should be provided by the municipalities. The work points out the steps that show how important it is to have a strategy or a clear concept of how to begin with such a serious issue as the presence of Fallopia japonica in riverbank vegetation and its eradication. This framework provides simple steps that cannot be excluded when a municipality start actions against Fallopia japonica. All the indicators used in the model are based on the information known about Fallopia japonica that are presented in the literature.

The Seed Bank Response of Five Pioneer Plants to Flooding – A Implication for Riverbank Vegetation Restoration

The seed bank response of five pioneer plants, including Cynodon dactylon, Setaria viridis, Amorpha fruticosa, Alternanthera Philoxeroides and Xanthium sibiricum, to flooding were tested through simulating the flooding experiments. The flooding treatments included 30d, 60d, 90d and the control. All of the treated seeds were germinated under an appropriate germinate condition. The results showed that seed germination rate and germination index of Amorpha fruticosa and Xanthium sibiricum increased with the increasing flooding time meanwhile that of Setaria viridis and Alternanthera Philoxeroides decreased, and Cynodon dactylon germination decreased firstly and then increased with the increasing flooding time. The results suggested that flooding influenced significantly seed germination, and implicated that Amorpha fruticosa, Cynodon dactylon and Amorpha fruticosa were appropriate species for the construction of artificial seed bank to restore riverbank vegetation in the Three Gorges reservoir area.