The role of the mahogany tree (Swietenia macrophylla King) on quantity and quality of water that fall below the canopy

Mahogany trees (Swietenia macrophylla) are often planted in urban forests area. This shady-crowned tree has a role in controlling the quantity and quality of rainwater that falls to the ground. Mahogany trees also affect the quality of rainwater through interception, fall, and stemflow. The purpose of this research was to determine the impact of the interception process, such as throughfall and stemflow, on changes in rainwater quality of the mahogany tree. The Data that needed to be measured were tree dimension, rainfall interception, and rainwater quality. Interception measurement was performed by calculating the number of throughfall and stemflow in one month-measurement. While the measurement of rainwater quality was measured once in the laboratory. These water quality measurements include Electrical Conductivity (EC), hardness, the content of Elements Ca, Mg, Na and K, and pH concentrations. The results based on the total area of the crown showed that mahogany had an interception value of 18.088%. In the throughfall measurement, the mahogany has a throughfall of 81.799%, while the amount of the stemflow is only 0.113%. The correlation of interception values, throughfall, and stemflow with rainfall are in general positively correlated. That means the higher rainfall water will increase the number of interception, throughfall, and stemflow. The results on water quality measurement explain that Ec value in rainwater interception was increased compared to water produced from rainfall in mahogany trees. It also has the same condition in hardness measurement. In pH measurements, the interception of rainwater has less pH when compared to direct rainfall water. In addition, the content of Elements Ca, Mg, K, and Na in Stemflow and Throughfall water have more numbers than rainfall itself.

The determinant factors for macroinvertebrate assemblages in a recreational river in Negeri Sembilan, Malaysia

The determinant factors for macroinvertebrate assemblages in river ecosystems are varied and are unique and specific to the type of macroinvertebrate family. This study aims to assess the determinant factors for macroinvertebrate assemblages in a recreational river. The study was conducted on the Ulu Bendul River, Negeri Sembilan, Malaysia. A total of ten sampling stations were selected. The research methodology included (1) water quality measurement, (2) habitat characterization, and (3) macroinvertebrate identification and distribution analysis. The statistical analysis used in this study was canonical correspondence analysis (CCA) to represent the relationship between the environmental factors and macroinvertebrate assemblages in the recreational river. This study found that most of the families of macroinvertebrates were very dependent on the temperature, DO, NH3-N, type of riverbed, etc. All of these factors are important for the survival of the particular type of macroinvertebrate, plus they are also important for selecting egg-laying areas and providing suitable conditions for the larvae to grow. This study advises that improved landscape design for watershed management be implemented in order to enhance water quality and physical habitats, and hence the protection and recovery of the macroinvertebrate biodiversity.

Stakeholder perception for groundwater management from a subsidence point of view in the Guadalentín Valley (Spain)

<p>Land subsidence produced from the exhaustive groundwater exploitation is a phenomenon that has critical effects in many areas around the world, especially in water-scarce areas. Among the objectives of the RESources managEment by integrating eaRth observation deriVed monitoring and flOw modelIng Results (RESERVOIR) project (GA nº 1924), one of them is the identification of the stakeholder requirements and groundwater conceptual model setup for several pilot sites. The present work is related with the Alto Guadalentín aquifer study case (SE Spain). To achieve the mentioned objective, a workshop was organized and a large number of potential stakeholders from local authorities, environmental agency, water supply companies, NGOs, insurance companies and regulatory institutions were summoned. During the workshop most important RESERVOIR activities were presented. Once the workshop was finished, a questionnaire that proposes the evaluation of the main problems in the area related to the groundwater management was sent to all participants. Results disclose that 55% of stakeholders consider that the principal problem in the Guadalentín aquifer is the overexploitation, and 50% of stakeholders regard that the lack of managerial, planning, and technical instruments are the most relevant issues to be addressed and solved. In more detail, the survey reveals that the monitoring coverage is inadequate in terms of: (a) groundwater levels monitoring (50%); (b) water quality measurement frequency (40%); and (c) water quality measurement points spatial distribution (55%) Even that area is reporting the highest subsidence rates in Europe, this problem is not considered as the most important, probably because affects agricultural areas and minimal damages were reported. Finally, 90% of the stakeholders have previous knowledge about groundwater modelling, but only 45% within them have information about the specific applications for which the model is employed in the Alto Guadalentín aquifer. Main conclusion leads to confirm that the measurements taken in the past have proved to be insufficient to reverse the state of the overexploitation of the aquifer. From this, some management measures must be strengthened, and several technical tools should be introduced to improve the groundwater management. On the other hand, improving the use of the numerical model of the Alto Guadalentín aquifer to support decision-making, as well as, updating the model by coupling it with the subsidence phenomenon through the definition of subsidence risk indexes would lead to a sustainable and holistic groundwater management.</p>

PENGARUH PEMBANGUNAN TURAP BETON TERHADAP EKOLOGI KAWASAN PERMUKIMAN DI TEPIAN SUNGAI KAPUAS PONTIANAK

Untuk menjaga daratan dari abrasi salah satu rekayasa teknik adalah menggunakan turap beton. Pembangunan turap beton hampir disepanjang tepian Sungai Kapuas Pontianak, menjadi program pemerintah daerah untuk menciptakan “Pontianak Waterfront City”. Namun dalam pelaksanaannya memiliki dampak terhadap ekologi khususnya pada kawasan permukiman di tepian Sungai Kapuas, hal ini terjadi karena sistem sanitasi baik limbah cair dan padatnya langsung dialirkan ke sungai, dengan asumsi akan terbawa oleh arus pasang-surut Sungai Kapuas. Dengan adanya turap limbah tersebut tertahan di lingkungan permukiman, kondisi ini tentunya akan mempengaruhi kualitas air dan ekologi pada kawasan. Dengan menggunakan metode pengukuran kualitas air sungai yaitu TSS, TDS, DO, COD dan BOD, yang diidentifikasi dan diukur, kemudian dilanjutkan dengan analisa kawasan, melalui pendekatan dari aspek fisik, aspek biologi dan aspek kultural. Analisa kawasan dilakukan dengan membandingkan dua lokasi kawasan permukiman di tepian Sungai Kapuas yang memiliki turap dan yang tidak memiliki turap. Hasil yang didapat adalah kawasan permukiman dengan turap beton, memiliki nilai TDS yang tinggi, DO yang rendah, COD yang tinggi dan BOD yang rendah dibandingkan kawasan permukiman tanpa turap. Sehingga pembangunan turap beton pada kawasan permukiman di tepian Sungai Kapuas akan berdampak terhadap ekologi pada kawasan tersebut. THE IMPACT OF CONCRETE SHEET PILES DEVELOPMENT ON THE ECOLOGY OF SETTLEMENT AREA AT THE WATERFRONT OF PONTIANAK KAPUAS RIVERTo protect the land from abrasion, one of the engineering techniques is to use a sheet pile. The construction of concrete sheet piles along the waterfront of the Pontianak Kapuas River has become a regional government program to create the "Pontianak Waterfront City." However, in its implementation, it has an impact on ecology, especially in residential areas on the waterfront of the Kapuas River; this occurs because the sanitation system, both liquid, and solid waste, is flowed directly into the river, assuming the tides of Kapuas River will carry it. With sheet pile the waste material retained in a residential environment, this condition will undoubtedly affect the water quality and the ecology in the area. Using river water quality measurement methods, TSS, TDS, DO, COD, and BOD, identified and measured, then continued with site analysis, with approaches from physical, biological, and cultural attributes. Sites analysis is done by comparing the two settlement areas at the Kapuas River's waterfront with sheet piles and without sheet piles. The results obtained are settlement areas with concrete sheet piles, which have high TDS values, low DO, high COD, and low BOD compared to settlement areas without sheet piles. The construction of concrete sheet piles in settlement areas at the waterfront of the Kapuas River will impact the areas' ecology