著者
加藤 琢磨 手計 太一 土屋 修一 山田 正
出版者
Japan Society of Civil Engineers
雑誌
水工学論文集 (ISSN:09167374)
巻号頁・発行日
vol.52, pp.277-282, 2008 (Released:2010-08-25)
参考文献数
7

We carry out the microclimate field observation collaborated closely with local residents in the downtown of Tokyo in order to study the effect of watering on urban climatic environment. Local residents sprinkled recycled water which was rainfall and/or bath water in summer. Then we measured air temperature, humidity, solar radiation, aerosol number, wind velocity and wind direction all the day. We could observe atmospheric phenomena before/after watering. The following conclusions were obtained: 1) Air temperature at almost all observation stations were started to decrease immediately after watering started. Area-averaged air temperature declined by 0.5 deg. C. After Watering, it took an average time of 60 minitues to relapse to the air temperature immediately before the sprinkling. 2) Surface temperature of roadway decreased from 50 deg. C to 40 deg. C compared between before and after Watering. Assuming the surface of roadway could be black body, long-wave radiation declined from 620 W/m^2 to 510 W/m^2 compared between before and after watering. Heat environment mitigation action by watering could be divided into “fall of air temperature” and “restraint of radiation”.
著者
大槻 順朗 大八木 豊 島谷 幸宏 朴 埼〓
出版者
Japan Society of Civil Engineers
雑誌
水工学論文集 (ISSN:09167374)
巻号頁・発行日
vol.52, pp.361-366, 2008 (Released:2010-08-25)
参考文献数
9

Urban development causes serious changes to watershed conditions by decreasing storage area, introducing pavement and channeling. As a result, the peak discharge has been increasing and the arrival time of peak becomes early. The purpose of this study is to investigate the state of retention facilities such as irrigation ponds and paddy area in Mikasa River watershed. The result of investigation shows the rate of the capacity of flood control of dam, ponds and paddy area are 37.1%, 14.6%, 48.3% and total capacity is 3, 063, 000m3.For the estimate of the storage facility effects, we applied the distributed runoff model considering ponds and paddy area effects. The result of calculation showed that the peak discharge at Sanno Bridge decreased 36m3/s by dam, 31m3/s by ponds and 36m3/s by paddy area.
著者
大八木 豊 島谷 幸宏 杉本 知佳子 加藤 憲介 朴 埼〓
出版者
Japan Society of Civil Engineers
雑誌
水工学論文集 (ISSN:09167374)
巻号頁・発行日
vol.50, pp.325-330, 2006 (Released:2010-11-30)
参考文献数
10

Urban developments cause serious changes to watersheds conditions by decreasing storage area, introducing pavement and channeling. As a result, the peak discharge has been increasing and the arrival time of peak flow becomes early. The purpose of this study is to investigate the empty capacity of irrigation ponds in the Mikasa River watershed and to clarify flood control capacity of them. The result of this study, the catchments area of all irrigation ponds was about 18%, the capacity of flood control was about 450, 000m3 in the Mikasa river watershed. To estimate the flood control ability of irrigation ponds, we applied the distributed runoff model considering ponds effects about flood disaster in July 19, 2003. The result of calculation showed that the peak discharge at the Sanno Bridge decreased 36m3/s by the irrigation ponds.
著者
狩野 学 手計 太一 木内 豪 榊 茂之 山田 正
出版者
Japan Society of Civil Engineers
雑誌
水工学論文集 (ISSN:09167374)
巻号頁・発行日
vol.48, pp.193-198, 2004-02-01 (Released:2010-06-04)
参考文献数
8
被引用文献数
4 4

The large-scale social experiment, which many citizens including media representative participated for evaluating the effects of the watering on the “Heat Island Effect”, was carried out in Tokyo Metropolitan in Aug. 25 2003. About 14000l. water were sprinkled for about 20 minutes from noon. Air temperature and humidity were measured by moving observation system and fixed observation system at watering area in Eastern Tokyo. After the watering, the air temperature difference between outside and inside of watering area increases, and its difference was about 0.5°C. Temperature of watering area is lower than the temperature of outside area of watering after the watering. The effect of the watering was verified using the numerical simulation based on MM5. As a result of this analysis, air temperature degreased 2-2.5°C in watering area after the watering.
著者
前野 詩朗
出版者
Japan Society of Civil Engineers
雑誌
水工学論文集 (ISSN:09167374)
巻号頁・発行日
vol.51, pp.613-618, 2007 (Released:2010-08-25)
参考文献数
3

The rising backwater, which occurs due to the confluence of the Takahashi River and the Oda River, makes the water level rather higher during flood in the upstream of those rivers. The higher water level endangers embankments of those rivers. One of the possible means to reduce the water level is to relocate the present confluence site with the Oda River to the downstream site of the Takahashi River. This study aims to investigate the effect of the relocation of the confluence site using two-dimensional flow analysis. Numerical results under present river course condition were compared with the measured water level, and the effectiveness of the proposed analytical model was confirmed. It is also shown that the relocation of the confluence site has an effect to reduce the water levels of rivers considerably.
著者
土屋 修一 加藤 拓磨 手計 太一 山田 正
出版者
Japan Society of Civil Engineers
雑誌
水工学論文集 (ISSN:09167374)
巻号頁・発行日
vol.49, pp.367-372, 2005-02-01 (Released:2011-06-27)
参考文献数
6

The social experiment was carried out for the purpose of the mitigation of the heat island effect by watering on August 18th to 25th. The microclimate observation has been carried out at watering area in Eastern Tokyo. As the results, the effect of the watering on the thermal environment in urban area was evaluated as decreasing effect on temperature. The following results were obtained; 1) The temperature variation in the daytime is included to be different every site because of the dispersion of surface temperature. 2) The air temperature in the experiment area is from 2 to 9 [degree] higher than temperature in thermometer shelter by the effect of long radiation. 3) The temperature decrease instantaneously when watering starts. 4) The temperature decreases 0.66 [degree] on average, 1.93 [degree] on maximum after the watering. 5) Total amount of decreasing temperature is decreased linearly by the distance from the point of watering.
著者
石井 宏明 神田 学 森脇 亮 奥園 孝二
出版者
Japan Society of Civil Engineers
雑誌
水工学論文集 (ISSN:09167374)
巻号頁・発行日
vol.43, pp.233-238, 1999
被引用文献数
2

Field observation was performed on two islands located in Tokyo Bay to investigate the atmospheric environment over Tokyo Bay by using Radio Sonde, Dopper Sodar and airplane in summer 1998.<BR>The following results were obtained; 1) The atmospheric boundary layer (ABL) over Tokyo Bay was composed of multiple layers.Especially, it was composed of three layers on August 10. 2) These multiple layers were formed by the effect of various kinds of return flows from the land. The upper boundary layer about 1250-2000m over Tokyo Bay was hotter and drier than the one over the land. 3) The airplane observation suggests that the air pollutant might be more concentrated over Tokyo Bay rather than over the land due to the difference of the boundary layer structure.
著者
松本 大毅 広城 吉成 堤 敦 神野 健二 新井田 浩
出版者
Japan Society of Civil Engineers
雑誌
水工学論文集 (ISSN:09167374)
巻号頁・発行日
vol.49, pp.127-132, 2005-02-01 (Released:2011-06-27)
参考文献数
11

Sayanokami spring water exists in the new campus of Kyushu University, which is located on the western part of Fukuoka City. This spring water is one of the important water resources for agriculture around the new campus area. The construction of the new campus started last June, 2000. In this study, to understand the hydrological properties of the Sayanokami circumference, 222Rn and tritium were used as tracers, respectively. Consequently, it was found out that the residence time of Sayanokami spring water is 10-20 years. Moreover, the residence time and the catchment area of Sayanokami spring water were estimated using groundwater flow model. As a result, the residence time of Sayanokami spring water was evaluated to be about 25 years at most and the catchment area was specified. It is concluded that the accuracy of estimation of residence time and catchment area of the spring water can be improved by analysis of radioactive isotopes and groundwater flow model.
著者
松永 信博 増田 壮佑 中牟田 大嗣 徳永 貴久 矢野 真一郎 押川 英夫 橋本 彰博 藤田 和夫 古賀 雅之 岩下 智明 原田 敦彦
出版者
Japan Society of Civil Engineers
雑誌
水工学論文集 (ISSN:09167374)
巻号頁・発行日
vol.51, pp.1415-1420, 2007 (Released:2010-08-25)
参考文献数
11

Laboratory experiments were carried out on water quality purification by a porous concrete block including Bacillus subtilis natto group. The block is called EcoBio-Block (EBB). The time variations of biochemical oxygen demand (BOD) and chemical oxygen demand (COD) were obtained experimentally under the aerated condition by changing the weight ratio of EBB to water. The time variations of BOD and COD were expressed universally by normalizing the data. The reduction rate of BOD increases with the weight ratio. On the other hand, that of COD takes the maximum value at the weight ratio of 0.01 and decreases after that. The rapid reduction of BOD and COD seen in the early stage may be due to the adhesion or adsorption of organic matter by EBB. The mineralization of organic matter and the nitrification of NH4-N by EBB become active at the later stage and the activity increases with the weight ratio. It was experimentally revealed that EBB has also the very high ability for the water quality purification in the DO-saturated water and it depends strongly on the weight ratio of EBB to water.
著者
馬籠 純 竹内 邦良 金丸 茂男 石平 博
出版者
公益社団法人 土木学会
雑誌
水工学論文集 (ISSN:09167374)
巻号頁・発行日
no.46, pp.295-300, 2002

The purpose of this study is to understand the potential impact of reservoir induced water storage on the basin scale water cycle. In this study, the increase of the basin scale residence time of river water is used as the index of the effect of reservoir on water cycle, and its spatial and temporal distribution in Japan are demonstrated. The results of analysis show that the potential increase of residence time by dam reservoirs in Japan has gradually increased from 1960's and reached to 14.5 days in 1995. The actual residence time increase is also estimated in the Tone river basin where operation and seasonal variation of river discharge are taken into account. It is shown that the estimated actual residence time is much smaller than the potential, in the case of the Tone river basin, 45%.
著者
重枝 未玲 寺町 賢一 碇 正敬 高崎 秀一 松木 洋忠 秋山 壽一郎 中山 比佐雄 田邉 武司
出版者
公益社団法人 土木学会
雑誌
水工学論文集 (ISSN:09167374)
巻号頁・発行日
no.52, pp.829-834, 2008
被引用文献数
1

An analysis of behavior of over-land flows based on geophysical characteristics using geographic information system (GIS) was conducted. Firstly, the digital surface model (DSM), which is the data of the surface of ground, was verified against the data of bed elevation in the map of the city planning whose scale is 1/2500. Secondary, using digital surface model, a behavior of over-land flow was analyzed. Finally, the analyzed behavior of over-land flow was compared with the flood process examined in the field study and numerical simulation. It shows that the GIS and DSM are useful tool and data for examining the behavior of the inundation flows.
著者
M. A. ELZEIR T. HIBINO
出版者
Japan Society of Civil Engineers
雑誌
水工学論文集 (ISSN:09167374)
巻号頁・発行日
vol.43, pp.827-832, 1999-02-10 (Released:2010-08-25)
参考文献数
12
被引用文献数
1 1

The Suez Canal is an important water-transport route all over the world. Two hydrodynamic issues related to the flow within the canal are worthy of consideration: sedimentation in the northern section of the canal and high velocity current in the southern section of the canal. To address the sedimentation issue, a large program of dredging works is being undertaken. A numerical model is presently being developed to simulate flow in the canal with a special attention paid to the south part. This model is the focus of the present study. The model is a two-dimensional depth averaged finite element model utilizing independent open boundaries at the north and south ends of the canal. The radiation and modified long wave boundary conditions are compared. Due to its accuracy and flexibility to suit different forcing conditions, the radiation boundary condition shows superiority over the modified long-wave formulation. The simulation results reflect most of the physical phenomena observed in the canal.
著者
宇多 高明 木暮 陽一 平野 一彦 大内 香織 三波 俊郎 熊田 貴之
出版者
Japan Society of Civil Engineers
雑誌
水工学論文集 (ISSN:09167374)
巻号頁・発行日
vol.51, pp.1325-1330, 2007 (Released:2010-08-25)
参考文献数
8

Numerical simulation using the contour line change model was carried out to restore the sandy beach on the lakeshore in Ukishima area in Lake Kasumigaura. Past aerial photographs were compared to investigate the long-term shoreline changes of the Wadamisaki sand spit formed in the southeast part of the lake. The predominant wave direction of wind waves was determined from the shoreline changes in Ukishima area. Given the wave height predicted using the SMB method and predominant wave direction, the optimum arrangement of groins was determined using the contour line change model considering the effect of grain size changes.
著者
品川 守 舘谷 清 山口 甲
出版者
公益社団法人 土木学会
雑誌
水工学論文集 (ISSN:09167374)
巻号頁・発行日
no.36, pp.305-310, 1992
被引用文献数
2

Eighty years have passed since systematic improvement of the Ishikari River started in 1910. Before the improvements, the Ishikari River was in a completely natural state, and caused floods every year due to its meandering stream. The goal of the improvements was to further the development of Hokkaido by rcelaiming the vast marshes along the Ishikari River. The improvement work involved channel improvement of river, mainly by (1) excavating short-cuts to shorten the river and lower the flood stage, and (2) construction of continuous embankments to prevent floods.<BR>As a result, flood protection has improved remarkably and allowed the development of new residential areas. Flood prevention and reduction in water-levelsby the short-cuts have changed the Ishikari Marshes to fertile arable land.<BR>This study will clarify how channel improvements in the Ishikari River executed for regional development contributed to a change in flood flows and decreases in floods.
著者
品川 守 舘谷 清 山口 甲
出版者
Japan Society of Civil Engineers
雑誌
水工学論文集 (ISSN:09167374)
巻号頁・発行日
vol.36, pp.305-310, 1992-02-20 (Released:2010-06-04)
参考文献数
2
被引用文献数
3 2

Eighty years have passed since systematic improvement of the Ishikari River started in 1910. Before the improvements, the Ishikari River was in a completely natural state, and caused floods every year due to its meandering stream. The goal of the improvements was to further the development of Hokkaido by rcelaiming the vast marshes along the Ishikari River. The improvement work involved channel improvement of river, mainly by (1) excavating short-cuts to shorten the river and lower the flood stage, and (2) construction of continuous embankments to prevent floods.As a result, flood protection has improved remarkably and allowed the development of new residential areas. Flood prevention and reduction in water-levelsby the short-cuts have changed the Ishikari Marshes to fertile arable land.This study will clarify how channel improvements in the Ishikari River executed for regional development contributed to a change in flood flows and decreases in floods.
著者
辻本 浩史 後藤 祐輔 竹下 航 田中 創
出版者
Japan Society of Civil Engineers
雑誌
水工学論文集 (ISSN:09167374)
巻号頁・発行日
vol.50, pp.559-564, 2006 (Released:2010-08-25)
参考文献数
8

The large and severe typhoon No.14 passed through along the west Kyusyu on September 4th-7th, 2005. The speed of typhoon was low, so, the heavy rainfall continued for a long time. Total rainfall of many observation points exceeded the maximum record and the water level of Ooyodo River, Komaru River and Gokase River exceeded the high water. 15, 000 or more people in Miyazaki city and 50, 000 or more people in Nobeoka city were ordered to refuge. A lot of meteorological information was able to get by internet-web-sites . Among them, the accuracy of the forecast information of 24 hours rainfall and the efficiency of the spatial and temporal information of flood risks was verified. As the results, it was shown that these information which support self-help, co-help of inhabitants are useful for the disaster prevention.
著者
大本 照憲 藤見 俊夫 小場 隆太
出版者
Japan Society of Civil Engineers
雑誌
水工学論文集 (ISSN:09167374)
巻号頁・発行日
vol.52, pp.451-456, 2008 (Released:2010-08-25)
参考文献数
5
被引用文献数
8 2

There are two measures to reduce human damage resulting from a flood flow, that is, preventive public facilities as hardware-like aspect and residents' evacuation from inundation flow risk as software-like aspect. Since the former has a practical limit when the facilities are attacked by the flood flow beyond their strength, at that time the latter becomes important. From this viewpoint, we picked up six areas from the Sendai river basin affected by flood disaster at the latter half of July in 2006 and executed questionnaire survey to the residents about evacuation activities, needs of disaster information, understanding of flood hazard map and awareness to flood disaster. Moreover, we analyzed effects of disaster forces on evacuation activity. This paper showed that social cohesion played an important part in a community's ability to respond to flood disasters.
著者
和田 一範 村瀬 勝彦 冨澤 洋介
出版者
Japan Society of Civil Engineers
雑誌
水工学論文集 (ISSN:09167374)
巻号頁・発行日
vol.49, pp.493-498, 2005-02-01 (Released:2011-06-27)
参考文献数
7
被引用文献数
4 4

The influence of global warming on hazard risk is estimated from the results of the regional climate model by Japan Meteorological Agency and Meteorological Research Institute. The horizontal resolution of the model is about 20km and the model outputs are expected to be useful for the risk assessment of the future. Before beginning the risk assessment, the model output values during 1981-2000 were verified by comparing with observed precipitation data. The verification shows that the precision of the models are generally well in representation of the precipitation, the normal value of the monthly precipitation and the annual maximum daily precipitation in each region. According to the analysis from the model outputs, the extreme daily precipitation in 100-yr time period will increase in some parts of western Hokkaido, northern Tohoku region, Hokuriku region and Nansei islands during 2081-2100. While, the result of the seasonal variation of precipitation shows that the precipitation will decrease especially in many areas in Japan except Hokkaido region from winter to spring, and the drought risk will increase there.
著者
中村 要介 土屋 十圀
出版者
Japan Society of Civil Engineers
雑誌
水工学論文集 (ISSN:09167374)
巻号頁・発行日
vol.50, pp.361-366, 2006 (Released:2010-11-30)
参考文献数
17

This study estimated the safety degree of flood control at Yattajima, the Tone River, Japan to verify effects of additional dams. Rainfall events considered are Catherine Typhoon in 1947, Ise Bay Typhoon in 1959, the Typhoon No. 15 in 1981, and the Typhoon No. 5 in 1998. The storage function method was used for runoff analysis, which showed good agreement between observed and computed discharges. Using the spatiotemporal rainfall pattern of Catherine Typhoon, this study simulated rainfall-runoff at each time stage; 1959 with two dams, 1981 with five dams, and 1998 with six dams (the same as present situation), and evaluated the effect of these added dams on flood control in terms of the decrease of peak discharge at Yattajima. The decreases estimated were 513-1, 253 m3/s for the 1959 situation; 2, 025-2, 765 m3/s for 1981; and 2, 233-2, 973 m3/s for 1998. It is also verified that the present situation with six dams can cope with 200-year floods, which is significant improvement because the past situation without dams could cope with 100-year floods.
著者
早川 敬之 藤田 昌史 芳賀 弘和 坂本 康
出版者
Japan Society of Civil Engineers
雑誌
水工学論文集 (ISSN:09167374)
巻号頁・発行日
vol.49, pp.1531-1536, 2005-02-01 (Released:2011-06-27)
参考文献数
7

It is necessary to evaluate the characteristics of river environment for planning river works and for setting an environmental target of preservation and improvement of habitats. Therefore the technique to analyze the relation between the distribution of living things and physical, chemical and biological environments of river habitats is required. In this paper, we presented an integrated water quality index and an integrated river flow type index. The latter was based on results of principal component analysis applied to the factors involved in HIM (Morishita, 1998). The integrated indices were used as criterion variables for a multiple regression analysis of fish data and some indicator species were presented. The multiple regression model was used for the estimation of integrated index values of verification rivers and showed good performance.