| 51. |
- Hamdan, Ahmed Naseh Ahmed, et al.
(författare)
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Rainfall-runoff modeling using the hec-hms model for the al-adhaim river catchment, northern iraq
- 2021
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Ingår i: Hydrology. - : MDPI AG. - 2306-5338. ; 8:2
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Tidskriftsartikel (refereegranskat)abstract
- It has become necessary to estimate the quantities of runoff by knowing the amount of rainfall to calculate the required quantities of water storage in reservoirs and to determine the likelihood of flooding. The present study deals with the development of a hydrological model named Hydrologic Engineering Center (HEC-HMS), which uses Digital Elevation Models (DEM). This hydrological model was used by means of the Geospatial Hydrologic Modeling Extension (HEC-GeoHMS) and Geographical Information Systems (GIS) to identify the discharge of the Al-Adhaim River catchment and embankment dam in Iraq by simulated rainfall-runoff processes. The meteorological models were developed within the HEC-HMS from the recorded daily rainfall data for the hydrological years 2015 to 2018. The control specifications were defined for the specified period and one day time step. The Soil Conservation Service-Curve number (SCS-CN), SCS Unit Hydrograph and Muskingum methods were used for loss, transformation and routing calculations, respectively. The model was simulated for two years for calibration and one year for verification of the daily rainfall values. The results showed that both observed and simulated hydrographs were highly correlated. The model’s performance was evaluated by using a coefficient of determination of 90% for calibration and verification. The dam’s discharge for the considered period was successfully simulated but slightly overestimated. The results indicated that the model is suitable for hydrological simulations in the Al-Adhaim river catchment.
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| 52. |
- Hamed Abd El Mageed, Yasser, et al.
(författare)
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Spatial variability of soil water content and salinity in a semi-arid agricultural field
- 2014
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Ingår i: Vatten: tidskrift för vattenvård /Journal of Water Management and research. - 0042-2886. ; , s. 151-157
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- One technique for collecting rainwater and prevent soil erosion applied on large areas in Tunisia involves theuse of soil ridges (1–1.5 m high). These contour ridges are constructed parallel to topographical isolines. Theeffects of the contour ridges on the soil water content (θ) distribution, bulk soil salinity σa, and soil water salin-ity (σw) were investigated in the catchment of El-Gouazine in central Tunisia. In total 258 measuring pointswere obtained in an 80 m x 120 m area. Spatial maps of σw, σa, and θ displayed essentially a random variationand no apparent pattern within the sampling area. A geostatistical analysis, however, displayed spatial correla-tion for all variables. A variational analysis displayed small measurement errors as compared to small-scale vari-ation in the soil. A potential risk with soil ridges could be salt accumulation just upstream the ridges, however,no such effect could be observed in the studied area.
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| 53. |
- Haridy, Sahar, et al.
(författare)
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Mapping of non-aqueous phase liquids using time domain reflectometry
- 2011
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Ingår i: Vatten: tidskrift för vattenvård /Journal of Water Management and research. - 0042-2886. ; , s. 123-130
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Ett tvådimensionellt transportförsök utfördes i en behållare (45 cm x 54 cm x 20 cm) fylld med fin sand. En färgad icke vattenlöslig vätska (LNAPL) spreds över en rektangulär yta, 5 x 20 cm, på försöksytan. Spridningen gjordes i fyra omgångar på olika sätt; med konstant flöde, konstant nivå och varierande nivå. Fyrtiotvå tidsdo män reflektometri (TDR) prober användes för att följa LNAPL transporten. Förutom TDR proberna följdes också transporten av LNAPL med en digital kamera som tog bilder av den transparanta framsidan på behålla ren. Resultaten visar att TDR mätningarna kunde detektera transporten av LNAPL. Felet i mätningarna var 0.01 m3 m–3 för vattenhaltsmätningen och 0.045 m3 m–3 för LNAPL-mätningen. Resultaten visar att TDR är en lovande metod för att följa utbredningen av LNAPL i marken.
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| 54. |
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| 55. |
- Heydarzadeh, Reza, et al.
(författare)
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Dissolved oxygen determination in sewers using flow hydraulic parameters as part of a physical-biological simulation model
- 2022
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Ingår i: Journal of Hydroinformatics. - 1464-7141. ; 24:1, s. 1-15
-
Tidskriftsartikel (refereegranskat)abstract
- This paper aims to develop a model for calculating the hydraulic and water quality parameters of wastewater within sewers. Information from the wastewater collection network and the transmission line in Birjand were used to verify the model performance. The parameters used for modelling quality changes include the yield constant for biomass (YH), the maximum specific growth rate (μH), the saturation constant for dissolved oxygen (KOG) and the saturation constant for readily biodegradable substrate within a biofilm (KSF), as well as the Gauckler-Manning-Strickler coefficient (n). They were selected from references and were verified at the calibration stage comparing measurements with the modelling values. Inputs of the created model are the average concentrations of dissolved oxygen and chemical oxygen demand of the incoming wastewater, the flow rate of wastewater at the exit point of the network, physical characteristics of the pipes and the height of drops within the sewer network. The amount of dissolved oxygen at different positions of the sewer network was calculated. The acceptable calculated sum of squares of errors and the correlation coefficient (R2) of the calibrated model for dissolved oxygen were 1.6872 and 0.77, respectively.
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| 56. |
- Heydarzadeh, Reza, et al.
(författare)
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Multiobjective Optimization in Sewer Network Design to Improve Wastewater Quality
- 2019
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Ingår i: Journal of Pipeline Systems Engineering and Practice. - 1949-1190. ; 10:4
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Tidskriftsartikel (refereegranskat)abstract
- Sewers that constitute the main part of wastewater systems can be used as pretreatment units of wastewater treatment plants. The authors aim to increase the treatment efficiency of sewers by optimization. A hydraulic model is written and validated. A quality calculation section is added to the model according to the Wastewater Aerobic/Anaerobic Transformations in Sewers (WATS) method, and it is calibrated and verified using the data of a real wastewater transition line. An optimization engine is coupled to the proposed model. The new model can simulate the hydraulic and quality parameters of a sewer network and optimize it. Six objective functions and a general one with their decision variables were assessed. A predesigned wastewater collection network was used for the optimization of five scenarios. The results can be used to identify optimization priorities at the network design stage. Results showed that an increase in the removal of organic matter within the sewer can be achieved, but its other performance indices may worsen. Prioritization of objectives according to stakeholder views is required.
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| 57. |
- Hogland, William, et al.
(författare)
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Assessment of stormwater pollution transport to swedish coastal waters
- 2018
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Ingår i: Integrated Stormwater Management. - : CRC Press. - 0873718054 - 9781315894652 - 9781351082204 ; , s. 81-92
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Bokkapitel (refereegranskat)abstract
- Studies dealing with stormwater pollution transport on a local scale have been carried out in Sweden since the middle of the 1970s. 1-7 However, so far no investigation has aimed at determining the importance of stormwater pollution on a larger scale, involving a region or a part of the country. Such studies would provide the necessary background information for (1) developing a regional (nationwide) stormwater management policy, (2) quantifying the importance of stormwater pollution in comparison with other pollution sources, and (3) helping to set the priorities between different measures taken to reduce the pollution transport to receiving waters.
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| 58. |
- Hogland, W., et al.
(författare)
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Calculation of mass transport of pollutants via storm water discharge
- 1986
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Ingår i: VATTEN. - 0042-2886. ; 42:1, s. 16-20
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Tidskriftsartikel (refereegranskat)abstract
- The National Swedish Environmental Protection Board recommends a standard value method for calculation of mass transport of pollutants via storm water sewer systems. In this paper mass transport calculations based on this method are compared with actual measurements. Measurements during one and a half years in the city of Lund show high amounts of leakage and drainage into the storm water sewer system. The paper shows that the pollution transport during base flow conditions is significant.
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| 59. |
- Hogland, W., et al.
(författare)
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Estimation of combined sewer overflow discharge from the city of Malmo.
- 1984
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Ingår i: Nordic Hydrology. - : IWA Publishing. - 0029-1277. ; 15:4-5, s. 333-340
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Tidskriftsartikel (refereegranskat)abstract
- A study aiming at the estimation of yearly volumes of CSO and yearly quantities of pollution load from CSO had been carried out in the city of Malmo, Sweden. Storm Water Management Model was used both to simulate single CSO events and for continuous simulation. The results from these simulations were compared with actual measurements.-from Authors
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| 60. |
- Hogland, William, et al.
(författare)
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ESTIMATION OF QUALITY AND POLLUTION LOAD OF COMBINED SEWER OVERFLOW DISCHARGE.
- 1984
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Ingår i: Urban Stormwater Management. - 9170321280 ; , s. 841-850
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Konferensbidrag (refereegranskat)abstract
- The relative effect of combined sewer overflow (CSO) discharge into receiving waters has increased during the last decades due to improved efficiency at treatment plants. In association with the rapid urbanization in the sixties and early seventies, new areas were connected to old sewer networks with limited capacity, leading to an increase in overflow volumes and, thus to an increase in pollution load. In order to develop a responsible urban water quality management policy we must be able to describe CSO in terms of quality and quantity. To elucidate such problems extensive measurements were carried out in the city of Malmo with quality sampling and simultaneous flow measurements. This paper presents different aspects on the quality of CSO discharge and different available methods for calculation of the pollution load.
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