Pertumbuhan dan Kandungan Agar Rumput Laut (Gracilaria spp) Pada Beberapa Tingkat Salinitas

The aims of this study was to know the salinity level which perform highest growth rate and agar contents on the Gracilaria spp in the homogen cultivation condition. This research was carried out in the Laboratory of SUPM Bone, and the Laboratory of faculty marine and fisheries science, Hasanuddin University, from July until October 2004. Fifteen peaces of wooden tanks with size 1 x 1 x 0.45 meters were used as experimental basins. Each basin contained sea water with 40 cm height. Gracilaria verrucosa, G. lichenoides, and G. gigas taken from the fishpond around the experimental location were used as experimental plants. Every basin was planted with 100 grams of seaweed using bottom method. The experimental design used was Randomised Block Design (RBD) with five salinity treatments, namely 10, 15, 20, 25, and 30 ‰. The results of this study showed that salinity of 20 ‰ (S3) and 25 ‰ (S4) gave highest daily growth rate, that was 2.40% and the highest agar contents (40.71%) was obtained at the salinity of 20 ‰ (S3).The daily growth rate of 10 permil (S1) salinity treatment reached its peak at week III, while the salinity treatment of 15 ‰ (S2), 20 ‰ (S3) salinity, 25 ‰ salinity (S4), and 30 ‰ salinity (S5) reached its peak in week IV.

Micro-scale hydrological field experiments in Romania

The paper (communication) presents an overview of hydrologic field experiments at micro-scale in Romania. In order to experimentally investigate micro (plot)-scale hydrological impact of soil erosion, the National Institute of Hydrology and Water Management founded Voineşti Experimental Basin (VES) in 1964 and the Aldeni Experimental Basins (AEB) in 1984. AEB and VES are located in the Curvature Subcarpathians. Experimental plots are organized in a double systems and have an area of 80 m

Characterization of sub-daily rainfall properties in three raingauges located in northeast Brazil

This paper aims to evaluate the characteristics of rainfall events of three experimental basins located in northeast Brazil. The study areas are located, one in Ceará State and two in Paraíba State. Thus, the definition of rainfall events was based on two characteristics: minimum inter-event time and minimum event depth. Then, they were classified according to the shape of the hyetograph: to the left rectangular, triangular, and triangular with peak, and to the right, bimodal and unshaped. Evaluation of the percentages of each type of hyetograph and the main characteristics of rainfall events (peak, duration and intensity) was carried out. The results shows that the two experimental basins located in the semi-arid region have similar characteristics, and shapeless events have significant accumulated rainfall.

Water storage in snow cover and runoff in experimental basins in the Jizerské hory Mountains

The main aim of this work was to compare the results of the water storages obtained in the experimental basins in the Jizerské hory Mountains before the time of snowmelt with the total outflows, which were measured in the hydrological stations during the snowmelt period in two winter seasons with extraordinary snow depths (2005 and 2006). The snow water equivalent (measured in weekly steps), daily precipitation amount, and runoff in hourly values were the input data; the calculated runoff coefficients were the output values. The runoff coefficients from the snowmelt periods of 2005 and 2006 were compared in the Uhlířská and the Jezdecká Basins. The runoff coefficient in the Uhlířská Basin increased in 2006 from 0.636 to 0.688 (increase by 4%) and in the Jezdecká Basin it increased in 2006 from 0.660 to 0.749 (increase by 9%). It may have been the result of a bigger volume of precipitation during the snowmelt period 2006. The calculated runoff coefficients, which express the differences between the water storage obtained and the total outflow, can describe the specific characters of the experimental basins. It may be useful for the estimation of the expected inflow into water reservoirs and also for the hydrological forecasting in the foothills of the Jizerské hory Mountains. The measured data of snow cover also serve as a check, and also for the possible adjustment of the snow water equivalent generated by the model SNOW 17 – which is a part of the forecasting modelling system Aqualog. This system is in everyday use for the Elbe river forecasts in the Forecasting Centre of CHMI. The usefulness of this procedure was proved especially during the floods arising from snowmelts in last years. The model SNOW 17 has been calibrated for the catchment of the Černá Desná Stream with the Jezdecká closing profile (one of the experimental basins in the Jizerské hory Mountains). The results obtained demonstrate a very good capability of the model to duplicate the dynamics of the snow cover accumulation and thaw, if quality input data are available.

Optimisation of operational management practices for the detention basins

The objective of this study is to develop new operational management practices for detention basins during rainfall events in order to limit flooding risk and, at the same time, to reduce pollutant discharges by optimising the settling process. For this work, a methodology was developed to study the integration of the stormwater treatment into existing detention structures. In this article, it was applied on two experimental sites. The current operation of the basins and “on/off” regulation studies were first carried out to quantify the freedom to act to change the control schemes. Relying on the support of these studies, new operational rules based on the current or “on/off” principle were then elaborated and tested on the experimental basins using a hydraulic model. Finally, their efficiency to protect against flooding and to reduce pollutant discharges was assessed.