Peak Discharge Volume Research Articles

Numerical Study on Filtration of Microparticle from Non-point Source

The impermeable area and the peak discharge volume have been consistently increasing due to widening of city development and renewal. Thus, distortion of water cycle has been serious problem compared to the past. When it comes to NPS pollution, lack of information on the load and characteristics of pollutants led to the insufficient reduction measures. Because the particles with size over 100 in road runoffs can go through gravitational sedimentation, they are controllable in grit chamber according to the structure of NPS pollution reduction facilities. In this section, using CFD model, the behavior of fluid and particle distribution according to structure characteristics of reduction facilities will be simulated and the optical condition for successful treatment in grit chamber will be calculated. As a result of study, numerical analysis about treatment of particulate pollutants with size greater than 100 for which gravitational sedimentation is possible showed that by controlling the inflow velocity the sedimentation efficiency could be improved and it is determined that maintenance will become facilitated through the installment of facilities such as baffles at grit chamber.

Hydrological simulation for impact assessment of Kaeng Sue Ten dam in Thailand

In 1980, Large dam project “Kaeng Sue Ten” was proceeded under the cabinet-council's conclusion. It was planned to be located at Song district in Phrae province on the upstream of the Yom River, Thailand. The purposes of this dam are irrigation and flood mitigation. Unfortunately, the troubles had occurred before the dam was built. The inhabitant who suffered from this project and Non-Governmental Organization (NGO) protested the construction of the dam. Until now, Kaeng Sue Ten dam has not been built yet. However, it is necessary to examine the effect of a new dam construction on the Yom River. We evaluated the impact of the Kaeng Sue Ten dam on seasonal water discharge and suspended sediment transport using hydrological simulations of target year 1995 (representative year of the great flood in the Yom River) and 2001 (representative year of the normal flow in the Yom River). Our study area was the main channel of the Yom River in northern Thailand. We used the 1-km distributed flow routing model (1KFRM) to calculate seasonal change of water discharge at four points. Sediment load was calculated from a regression equation between sediment load and water discharge, using suspended sediment concentrations in monthly river samples taken at two gauging stations. Finally we estimated annual sediment load along the study reach using from both of simulated annual hydrograph and the regression equation. Our simulation results show that after construction of dam, there was moderate decrease in peak discharge volume during rainy season (maximum decrease is 21.8%) and corresponding increase in the subsequent season (maximum increase is 40%). The impact of dam construction to the annual maximum discharge in high-water year was significantly larger than in water year 2001, indicating that the Kaeng Sue Ten operation will provide more effect on a high-flow year than a low-flow year. Accordingly, after dam construction, the sediment transportation decreased about 2% to 9.7% from its former value at Y.14 and Y.6 stations.

HYDROLOGICAL AND SEDIMENT TRANSPORT SIMULATION TO ASSESS THE IMPACT OF DAM CONSTRUCTION IN THE MEKONG RIVER MAIN CHANNEL

The downstream impact of dams is a complex problem in watershed management. In the upper Mekong River watershed and its main channel, dam construct ion projects were started in the 1950s to meet increasing demands for energy and food production. Dams called the Mekong Cascade were completed on the Mekong River in China, the Manwan Dam in 1996 and the Dachaoshan Dam in 2003. We evaluated the impact of the Manwan Dam and its related watershed development on seasonal water discharge and suspended sediment transportation using hydrologica l simulations of target years 1991 (before dam construction) and 2002 (after dam completion). Our study area was the main channel of the Mekong River in northern Thailand extending about 100 km downstream from the intersection of Myanmar, Thailand and Laos. We used the MIKE SHE and MIKE11 (Enterprise) models to calculate seasonal changes of water discharge and sediment transport at five points 15- 35-km apart in this interval. Sediment load was calculated from a regression equation between sediment load and water discharge, using suspended sediment concentrations in monthly river water samp les taken between November 2007 and November 2008. Finally we estimated annual sediment load alo ng the study reach using from both of simulated ann ual hydrograph and the regression equation. Our simulat ions showed that after construction of the dam, the re was a moderate decrease in peak discharge volume and during the rainy season in August and September and a corresponding increase in the subsequent mont hs. Accordingly, sediment transportation budgets we re increased in months after the rainy season. The sus pended sediment transportation in Chiang Sean was increased from 21.13 to 27.90 (M ton/year) in our m odel condition.

The impacts of urban discharges on the hydrology and water quality of an urban watercourse

This paper presents the findings of a study which has investigated the effects of urban discharges upon the hydrology and water quality of a small urban watercourse located in north London. A variety of hydrological variables and water quality parameters were monitored at a site downstream of two surface water outfalls (SWOs) and two combined sewer overflows (CSOs). Precipitation volume was found to be highly correlated with the total storm discharge (r2 = 0.91) and the duration of storm flow (r2 = 0.93). Precipitation intensity displayed a 0.67 level of correlation with peak discharge volume. Aqueous loadings of biochemical oxygen demand (BOD), nitrate, chloride, total ammonia, suspended solids and total and dissolved zinc, copper, cadmium and lead, increased during the five monitored storm events. The highest increases in pollutant loadings compared with dry weather values were associated with BOD and suspended solids.