Field observation of turbidity, chlorophyll and current velocity was conducted in the Barato River, which is the oxbow lake in the Ishikari River. In this oxbow lake resuspension of the sediment is main factor of water pollutant. In this survey, relationship among sediment resuspension, wind speed and current velocity were investigated. And the rate of sediment resuspesion was estimated by using observation results.Clear relationship exists between wind speed and turbidity when the wind speed was larger than certain level in each survey point. We tried to estimate the rate of sediment resupension by the methods in our study. The estimated value was generally adjusted to observed results in 2005; however, considerable difference was found in 2006.
{"title":"STUDY ON MOVEMENT OF SUSPENDED SOLID AND ESTIMATION OF SEDIMENT RESUSPENSION IN AN OXBOW LAKE","authors":"H. Yokoyama, S. Yamashita","doi":"10.2208/PROHE.52.1225","DOIUrl":"https://doi.org/10.2208/PROHE.52.1225","url":null,"abstract":"Field observation of turbidity, chlorophyll and current velocity was conducted in the Barato River, which is the oxbow lake in the Ishikari River. In this oxbow lake resuspension of the sediment is main factor of water pollutant. In this survey, relationship among sediment resuspension, wind speed and current velocity were investigated. And the rate of sediment resuspesion was estimated by using observation results.Clear relationship exists between wind speed and turbidity when the wind speed was larger than certain level in each survey point. We tried to estimate the rate of sediment resupension by the methods in our study. The estimated value was generally adjusted to observed results in 2005; however, considerable difference was found in 2006.","PeriodicalId":11343,"journal":{"name":"Doboku Gakkai Ronbunshuu B","volume":"46 2","pages":"1225-1230"},"PeriodicalIF":0.0,"publicationDate":"2008-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72610809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pandit Saroj Kumar, N. Shigeta, Y. Oka, M. Watanabe, Toru Kawasaki
Preissmann Slot concept is one of the most extensively accepted numerical approaches in unsteady free surface pressurized flow. However Courant's stability condition has imposed this method with limitation on the size of the time step. The slot concept produces large wave celerity and a corresponding strict time step limitation with too small slot width, while inaccuracies may result with too large slot width. The equations for a surcharged flow which form the lateral model are derived incorporating the relaxation effect and compared with corresponding equations of slot model. The friction loss is evaluated in slot model by introducing the coefficient, which modifies the slot model. The pair of differential equations of Slot Model and Modified Slot Model are solved and presented in forms for direct substitution into FORTRAN programming for numerical analysis. The numerical result justifies Modified Slot Model to be more efficient for the modeling of transient flow in sewer network.
{"title":"MODIFICATION OF SLOT MODEL BY COINCIDING WITH THE LATERAL MODEL","authors":"Pandit Saroj Kumar, N. Shigeta, Y. Oka, M. Watanabe, Toru Kawasaki","doi":"10.2208/PROHE.52.877","DOIUrl":"https://doi.org/10.2208/PROHE.52.877","url":null,"abstract":"Preissmann Slot concept is one of the most extensively accepted numerical approaches in unsteady free surface pressurized flow. However Courant's stability condition has imposed this method with limitation on the size of the time step. The slot concept produces large wave celerity and a corresponding strict time step limitation with too small slot width, while inaccuracies may result with too large slot width. The equations for a surcharged flow which form the lateral model are derived incorporating the relaxation effect and compared with corresponding equations of slot model. The friction loss is evaluated in slot model by introducing the coefficient, which modifies the slot model. The pair of differential equations of Slot Model and Modified Slot Model are solved and presented in forms for direct substitution into FORTRAN programming for numerical analysis. The numerical result justifies Modified Slot Model to be more efficient for the modeling of transient flow in sewer network.","PeriodicalId":11343,"journal":{"name":"Doboku Gakkai Ronbunshuu B","volume":"146 1","pages":"877-882"},"PeriodicalIF":0.0,"publicationDate":"2008-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80520385","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
There is the case to have to make the slope of the fishway steeper than the standard range, according to the geographical features condition. In this research, measurement of flow structure and observation of swimming behavior of Leuciscus hakonensis at the hydraulic model of the pool and weir type fishway with slope 1/5 were conducted. Main results are shown as follows; 1) Ascending rate of this species in TYPE C which has short pools in flowing direction is higher than in TYPE B which has big steps between each pools when the overflow depth equals 5-10 cm, ascending rate of this species over 9-10 cm in TYPE B is higher than in TYPE C when the overflow depth equals 15-20 cm. 2) The difference of flow structure doesn't necessarily greatly influence ascending rate of this species. 3) About this species, it is necessary to select TYPE B or C corresponding to the assumed range of the overflow depth.
{"title":"FLOW STRUCTURE AND SWIMMING BEHAVIOR OF LEUCISCUS HAKONENSIS AT POOL-AND-WEIR TYPE FISHWAY WITH SLOPE 1/5","authors":"Atsushi Namihira, M. Goto, Hiroyasu Kobayashi","doi":"10.2208/PROHE.52.1189","DOIUrl":"https://doi.org/10.2208/PROHE.52.1189","url":null,"abstract":"There is the case to have to make the slope of the fishway steeper than the standard range, according to the geographical features condition. In this research, measurement of flow structure and observation of swimming behavior of Leuciscus hakonensis at the hydraulic model of the pool and weir type fishway with slope 1/5 were conducted. Main results are shown as follows; 1) Ascending rate of this species in TYPE C which has short pools in flowing direction is higher than in TYPE B which has big steps between each pools when the overflow depth equals 5-10 cm, ascending rate of this species over 9-10 cm in TYPE B is higher than in TYPE C when the overflow depth equals 15-20 cm. 2) The difference of flow structure doesn't necessarily greatly influence ascending rate of this species. 3) About this species, it is necessary to select TYPE B or C corresponding to the assumed range of the overflow depth.","PeriodicalId":11343,"journal":{"name":"Doboku Gakkai Ronbunshuu B","volume":"240 1","pages":"1189-1194"},"PeriodicalIF":0.0,"publicationDate":"2008-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73628411","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The acquisition ratio of observational data by ocean radar presents a cyclic variation synchronized with tidal motion and an abrupt decreasing due to the meteorological conditions. Information relevant to the property of variation of the data acquisition and the impact factors on its variation is important for practical uses of ocean radar observation systems. The authors investigated the impact factors to the data acquisition ratio of the DBF(Digital Beam Forming) ocean radar with VHF band, central frequency 41.9MHz through long-term observation in Ariake Bay. As a result, the appearance of tidal flat along the coast off Arao mainly affected the cyclic variation of the data acquisition due to the transmission loss of radio waves. Besides, the flood from Chikugo River accompanied by heavy rainfalls and the decrease of conductivity at sea surface caused the abrupt decline of the acquisition ratio. At the term of weak wind less than 1m/s, the data acquisition also decreased by way of suppression of surface resonant wave.
{"title":"STUDY OF IMPACT FACTORS ON DATA ACQUISITION RATIO FOR DBF OCEAN RADAR WITH VHF BAND","authors":"T. Yoshii, S. Sakai, T. Tsubono, M. Matsuyama","doi":"10.2208/PROHE.52.1363","DOIUrl":"https://doi.org/10.2208/PROHE.52.1363","url":null,"abstract":"The acquisition ratio of observational data by ocean radar presents a cyclic variation synchronized with tidal motion and an abrupt decreasing due to the meteorological conditions. Information relevant to the property of variation of the data acquisition and the impact factors on its variation is important for practical uses of ocean radar observation systems. The authors investigated the impact factors to the data acquisition ratio of the DBF(Digital Beam Forming) ocean radar with VHF band, central frequency 41.9MHz through long-term observation in Ariake Bay. As a result, the appearance of tidal flat along the coast off Arao mainly affected the cyclic variation of the data acquisition due to the transmission loss of radio waves. Besides, the flood from Chikugo River accompanied by heavy rainfalls and the decrease of conductivity at sea surface caused the abrupt decline of the acquisition ratio. At the term of weak wind less than 1m/s, the data acquisition also decreased by way of suppression of surface resonant wave.","PeriodicalId":11343,"journal":{"name":"Doboku Gakkai Ronbunshuu B","volume":"99 1","pages":"1363-1368"},"PeriodicalIF":0.0,"publicationDate":"2008-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78347047","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
To investigate the impact of the actual sea surface temperature (SST) of Tokyo Bay on urban air temperature, an observation network was constructed. SST had been measured at 14 observation sites, such as the lighted buoy in Tokyo Bay since November 2006 to September 2007, and urban air temperature was simulated using the numerical modeling system, WRF, in which SST obtained from this observation was used. In this study, the following results are obtained.(1) From observational study, spatial distribution of air temperature is similar to that of SST, and air temperature over Tokyo Bay is considerably affected by air advection from the coastal land area.(2) Actual SST of Tokyo Bay has significant seasonal and diurnal variation compared with outer SST.(3) Air temperature at Tokyo increases about 0.1°C in summer if the outer SST is replaced with observed SST in Tokyo Bay in the numerical simulation.
{"title":"IMPACT OF THE ACTUAL SEA SURFACE TEMPERATURE OF TOKYO BAY ON URBAN AIR TEMPERATURE","authors":"R. Oda, M. Kanda, R. Moriwaki, Tadashi Yamada","doi":"10.2208/PROHE.52.283","DOIUrl":"https://doi.org/10.2208/PROHE.52.283","url":null,"abstract":"To investigate the impact of the actual sea surface temperature (SST) of Tokyo Bay on urban air temperature, an observation network was constructed. SST had been measured at 14 observation sites, such as the lighted buoy in Tokyo Bay since November 2006 to September 2007, and urban air temperature was simulated using the numerical modeling system, WRF, in which SST obtained from this observation was used. In this study, the following results are obtained.(1) From observational study, spatial distribution of air temperature is similar to that of SST, and air temperature over Tokyo Bay is considerably affected by air advection from the coastal land area.(2) Actual SST of Tokyo Bay has significant seasonal and diurnal variation compared with outer SST.(3) Air temperature at Tokyo increases about 0.1°C in summer if the outer SST is replaced with observed SST in Tokyo Bay in the numerical simulation.","PeriodicalId":11343,"journal":{"name":"Doboku Gakkai Ronbunshuu B","volume":"104 1","pages":"283-288"},"PeriodicalIF":0.0,"publicationDate":"2008-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77506343","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nature oriented hydraulic structures made of natural stones such as ripraps have been used in Japan considering river environment. Negative aspect of these structures is easy to collapse under intense flow. Therefore, a connect stone is proposed to increase its stability against the intense flow. In this study, stability of two types connected stones, one is non-porous and the other is porous type, was investigated under rapidly varied flow conditions such as supercritical flow and hydraulic jump. Stability analysis using uplift and drag force acting on the connected stone shows that the non-porous type connected stone may collapse turn up and lift up mode. Furthermore, it is clarified that the porous type connected stone is more stable than the non-porous type.
{"title":"EVALUATION OF HYDRODYNAMIC FORCE ON CONNECTED STONE BED PROTECTION WORKS AT THE DOWNSTREAM OF A WEIR","authors":"S. Maeno, A. Yamamura, Kimiko Kaseguma","doi":"10.2208/prohe.52.715","DOIUrl":"https://doi.org/10.2208/prohe.52.715","url":null,"abstract":"Nature oriented hydraulic structures made of natural stones such as ripraps have been used in Japan considering river environment. Negative aspect of these structures is easy to collapse under intense flow. Therefore, a connect stone is proposed to increase its stability against the intense flow. In this study, stability of two types connected stones, one is non-porous and the other is porous type, was investigated under rapidly varied flow conditions such as supercritical flow and hydraulic jump. Stability analysis using uplift and drag force acting on the connected stone shows that the non-porous type connected stone may collapse turn up and lift up mode. Furthermore, it is clarified that the porous type connected stone is more stable than the non-porous type.","PeriodicalId":11343,"journal":{"name":"Doboku Gakkai Ronbunshuu B","volume":"3 1","pages":"715-720"},"PeriodicalIF":0.0,"publicationDate":"2008-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76933144","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Sakai, Y. Nihei, K. Ehara, Miho Usuda, K. Shigeta, S. Ootsuka
Previous evaluation of pollutant loads for the basin of Tokyo Bay are not accurately treated with the influence of flood-flow conditions. In the present study, we attempt to clarify the nutrients and COD loads in the main influent rivers under hydrologic events. For this purpose, we mounted automatic water samplers at the Edo, Ara, Tama and Naka Rivers. The observed results indicate that specific relations between river discharge Q and water quality are found in each river. The pollutant loads in the Ara and Naka Rivers are dominant in flood and low flow conditions, respectively. The large amount of the nutrients and COD loads were transported under flood flow conditions in all rivers.
{"title":"NUTRIENT AND COD LOADS IN THE EDO, ARA, TAMA AND NAKA RIVERS UNDER FLOOD FLOW CONDITIONS","authors":"A. Sakai, Y. Nihei, K. Ehara, Miho Usuda, K. Shigeta, S. Ootsuka","doi":"10.2208/PROHE.52.1117","DOIUrl":"https://doi.org/10.2208/PROHE.52.1117","url":null,"abstract":"Previous evaluation of pollutant loads for the basin of Tokyo Bay are not accurately treated with the influence of flood-flow conditions. In the present study, we attempt to clarify the nutrients and COD loads in the main influent rivers under hydrologic events. For this purpose, we mounted automatic water samplers at the Edo, Ara, Tama and Naka Rivers. The observed results indicate that specific relations between river discharge Q and water quality are found in each river. The pollutant loads in the Ara and Naka Rivers are dominant in flood and low flow conditions, respectively. The large amount of the nutrients and COD loads were transported under flood flow conditions in all rivers.","PeriodicalId":11343,"journal":{"name":"Doboku Gakkai Ronbunshuu B","volume":"12 1","pages":"1117-1122"},"PeriodicalIF":0.0,"publicationDate":"2008-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82492643","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"MODELING OF SETTLING AND SEDIMENTARY PROCESSES CONSIDERING DECOMPOSITION OF ORGANIC MUD","authors":"T. Hibino, K. Nagao, Y. Matsunaga","doi":"10.2208/JSCEJB.64.202","DOIUrl":"https://doi.org/10.2208/JSCEJB.64.202","url":null,"abstract":"","PeriodicalId":11343,"journal":{"name":"Doboku Gakkai Ronbunshuu B","volume":"13 1","pages":"202-213"},"PeriodicalIF":0.0,"publicationDate":"2008-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78903525","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
F. Nishimura, Mami Sugaya, T. Akase, M. Masuda, M. Watanabe, H. Tsuno
In this study, water quality characteristics of citrus grove soil leachate were investigated. Citrus grove soil contains nitrogen and phosphorus in high concentrations due to the high amount of fertilization, and its soil pH is also very low. Therefore it is considered that not only nutrients but also some problematic materials such as Al and Pb for aquatic livings and ecosystem at the watershed can be contained in the leachate. It is also concerned that the materials can be discharged into the downstream site as a result. It is observed that pH of leachate is in the range of neutral, and the concentration of Al is not at the level where the aquatic livings and ecosystem can be affected. However, some heavy metals can be discharged and nutrients can cause eutrophication. It is suggested that citrus grove can be a big nonpoint source of nutrients.
{"title":"FIELD STUDY ON THE WATER QUALITY CHARACTERISTICS OF CITRUS GROVE SOIL LEACHATE","authors":"F. Nishimura, Mami Sugaya, T. Akase, M. Masuda, M. Watanabe, H. Tsuno","doi":"10.2208/PROHE.52.1135","DOIUrl":"https://doi.org/10.2208/PROHE.52.1135","url":null,"abstract":"In this study, water quality characteristics of citrus grove soil leachate were investigated. Citrus grove soil contains nitrogen and phosphorus in high concentrations due to the high amount of fertilization, and its soil pH is also very low. Therefore it is considered that not only nutrients but also some problematic materials such as Al and Pb for aquatic livings and ecosystem at the watershed can be contained in the leachate. It is also concerned that the materials can be discharged into the downstream site as a result. It is observed that pH of leachate is in the range of neutral, and the concentration of Al is not at the level where the aquatic livings and ecosystem can be affected. However, some heavy metals can be discharged and nutrients can cause eutrophication. It is suggested that citrus grove can be a big nonpoint source of nutrients.","PeriodicalId":11343,"journal":{"name":"Doboku Gakkai Ronbunshuu B","volume":"5 1","pages":"1135-1140"},"PeriodicalIF":0.0,"publicationDate":"2008-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76441176","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"AN OPTIMAL DESIGN FRAMEWORK OF A FLOOD CONTROL SYSTEM INCLUDING IN-FLOODPLAIN COUNTERMEASURES BASED ON DISTRIBUTED RISK ASSESSMENT —APPLICATION TO AN ACTUAL RIVER BASIN—","authors":"T. Hori, S. Furukawa, Akira Fujita, K. Inazu, S. Ikebuchi","doi":"10.2208/JSCEJB.64.13","DOIUrl":"https://doi.org/10.2208/JSCEJB.64.13","url":null,"abstract":"氾濫原（堤内地）における減災対策を組み込み，地先の安全度を基準とした治水計画の策定手法を由良川流域に適用し，複数のシナリオ下での最適解を求め，手法の適用性と問題点について考察した．具体的には，防御対象地域を38個のブロックに分割するとともに，ダムの嵩上げ，連続堤，輪中堤の建設，家屋・宅地嵩上げを中心とする施策から，対象地域全体の被害レベルを最小化する施策の組み合わせ，ならびに実施順序を遺伝的アルゴリズムを用いて決定した．その結果，洪水被害を人的被害，家屋等の被害，重要施設の被害の3つの側面からレベル化し，それらを総合して治水対策を評価する方法を用いることで，各施策オプションの持つ効果を反映した解が求められることが確認できた．","PeriodicalId":11343,"journal":{"name":"Doboku Gakkai Ronbunshuu B","volume":"48 1","pages":"13-23"},"PeriodicalIF":0.0,"publicationDate":"2008-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87936625","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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