Predetermination of flood flows by different methods: Case of the catchment area of the Biskra Oued (North-East Algeria)

Author(s):  
Amel Boumessenegh ◽  
Hadda Dridi
1986 ◽  
Vol 10 (11) ◽  
pp. 303-306
Author(s):  
Leonard Fagin ◽  
Harry Pursher

608 is a Community Mental Health Centre (CMHC) in Waltham Forest Health District which came into service in February 1983. It serves a catchment area in North East London of approximately 95,000, and caters primarily for the 16 to 65 age group. It is linked with the services provided by a large psychiatric hospital—Claybury—which has been scheduled for closure by 1993. Planning is now under way to provide alternative services in each of the five districts covered by the hospital.


2021 ◽  
pp. 2272-2285
Author(s):  
Ali Hussein Ali ◽  
Kamal K. Ali ◽  
Ayser M. Al-Shamma'a

 The results of the present study show that the highest elevation point is (912) meters (a.s.l.) inside Wadi Al-Khur basin while the lowest elevation point is (6) meters (a.s.l.) inside Wadi Abu-Talha basin. The biggest catchment area is represented by Wadi Al-Khur (48840 km²) whereas the smallest catchment area is Wadi Taqtaq (1748 km²). The stream direction of all streams trends from South-West towards North-East. The soil available water capacity (AWC) (Moisture Deficit) in the studied area was15 mm. The average annual rainfall was133.11 mm, the average annual temperature was 25.65 Co, the total depth amount of E Apanwas 3691.85 mm/year, the relative humidity was 40 %, the average annual sunshine is 7.9 hrs., and the average annual wind speed is 2.7 m/s. The water surplus of the total studied area 46800 km) was about 488.592 m³⁄year, while the runoff amount was about 442.190 m³ ⁄year.


Annually sedimentation causes 1 % of storage capacity of the reservoir all over the world. Blockage of intakes in the reservoirs and damage to tunnels/turbines can be also caused due to sediment inflow from the rivers in the catchment area. Due to the problems caused by sediments scouring of sediment from reservoir known as flushing is been done and this technique for removal of sediment is the most effective one. The process of flushing is done by lowering the water level necessarily to erode deposited sediment and also to flush them from/through the intakes and river catchment. The sediment size and other parameters such as the sediment characteristics within the catchment area of reservoir and technique used during the flushing process through the reservoir and also along the geometry of channel can be related to outflow sediment discharge. Run-of-the-river projects contribute a major part of power generation in India, but this type of projects face a very common problem of sediment accumulation in the reservoirs due to high amount of sediments coming from mountainous region. These sediments decrease the storage capacity of reservoir and also the life of turbine blades by choking and reacting with it. North and North-East India is facing severe problem of storage depletion in their reservoirs for the power generation. Hence, it is essential to keep proper sediment management plans in reservoirs of these types of projects during planning and design stage. This paper describes the prediction of sedimentation and flushing pattern in the reservoir of usual run of river project in Himalayan region, the paper describes the use of mathematical model simulations. The one dimensional HEC-RAS 5.0.3 was used as numerical modeling for the project and the results of flushing model was also. In this study, monsoon data was used to predict the year wise sedimentation pattern. Eight sets of transport equations (Ackers-White, Meyer Peter Muller, Engelund-Hansen, Laursen, Wilcock-Crowe, Yang, Toffaleti, MPM-Toffaleti.) were used with different sets of time interval to perform the study. The analysis of results and comparison with annual observed sediment volume indicated that simulations using HEC-RAS 5.0.3 with Ackers-White transport equation predicted the sediment load more accurately when the reservoir was operated at FRL. Hence, further studies for reservoir operating at FRL were carried out using the Ackers-White transport equation. Further, the worst condition of sediment accumulation was taken into flushing model to perform flushing analysis. Here, two different combinations of run were performed of 300 cumecs & 400 cumecs discharge for of 3, 6, 9, 12, 15, 18, 24, and 27 hours respectively. By analyzing the results coming from flushing runs, it was concluded that the run performed at FRL for 300 cumec discharge for 24 hours and 400 cumecs discharge for 15 & 18 hours were effective.


1996 ◽  
Vol 33 (4-5) ◽  
pp. 167-174 ◽  
Author(s):  
J. Gelbrecht ◽  
E. Driescher ◽  
H. Lademann ◽  
J. Schönfelder ◽  
H.-J. Exner

Water resources management in NE Germany is still confronted with the consequences of eutrophication. Since the majority of nutrient loading is of diffuse origin, an exact understanding of the various sources is a prerequisite to reducing their impact on surface waters. Control of diffuse pollution demands a “strategy of little steps”, i.e. a variety of numerous measures at different locations in the whole catchment area. The paper describes different nutrient sources, especially those of phosphorus, in a small catchment, provides data on the sources and amounts of pollution and demonstrates proposals and strategies for abatement (e.g. reduction of fertilizers, restoration of wetland and brook stretches, development of ponds). Among the different sources, subsurface water enriched with phosphorus, plays an essential role, because arable soils are oversupplied with phosphorus and the sorption capacity of several soils is nearly exhausted.


Antiquity ◽  
1976 ◽  
Vol 50 (200) ◽  
pp. 216-222
Author(s):  
Beatrice De Cardi

Ras a1 Khaimah is the most northerly of the seven states comprising the United Arab Emirates and its Ruler, H. H. Sheikh Saqr bin Mohammad al-Qasimi, is keenly interested in the history of the state and its people. Survey carried out there jointly with Dr D. B. Doe in 1968 had focused attention on the site of JuIfar which lies just north of the present town of Ras a1 Khaimah (de Cardi, 1971, 230-2). Julfar was in existence in Abbasid times and its importance as an entrep6t during the sixteenth and seventeenth centuries-the Portuguese Period-is reflected by the quantity and variety of imported wares to be found among the ruins of the city. Most of the sites discovered during the survey dated from that period but a group of cairns near Ghalilah and some long gabled graves in the Shimal area to the north-east of the date-groves behind Ras a1 Khaimah (map, FIG. I) clearly represented a more distant past.


1999 ◽  
Vol 41 (1) ◽  
pp. 26-39 ◽  
Author(s):  
Michele Bottos ◽  
Tatiana Granato ◽  
Giuseppa Allibrio ◽  
Caterina Gioachin ◽  
Maria Luisa Puato
Keyword(s):  

1999 ◽  
Vol 110 (5-6) ◽  
pp. 455-463 ◽  
Author(s):  
S. Güvenç ◽  
Ş Öztürk
Keyword(s):  

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