Emission predictions with a multi-linear reservoir model

1999 ◽  
Vol 39 (2) ◽  
pp. 9-16 ◽  
Author(s):  
G. Vaes ◽  
J. Berlamont
Keyword(s):  
Input Data ◽  
Reservoir Model ◽  
Combined Sewer Overflows ◽  
Detailed Model ◽  
Scenario Analyses ◽  
Combined Sewer ◽  
Physically Based ◽  
Ideal Tool ◽  
Linear Reservoir

For the assessment of combined sewer overflows detailed models are not necessary. Physically based conceptual models give an optimal balance between model uncertainty and uncertainty in the input data. Besides, it is important that continuous long term simulations are performed. To prove this, in this paper the calibration of a reservoir model is discussed. The emission results of the reservoir model are compared with those of a hydrodynamic model. This research shows that a well-calibrated reservoir model can predict overflow emissions as well as a detailed model, taking into account the uncertainties in the input data. Moreover, when a reservoir model is used the calculation times are 104 to 106 times smaller. Such simplified models are an ideal tool to perform quickly various scenario analyses.

scholarly journals Pollution Loads Discharged from Combined Sewer Overflows: Theoretical Approach and Long Term Numerical Assessment

1992 ◽  
Vol 23 (1) ◽  
pp. 27-48 ◽  
Author(s):  
Paolo Mignosa ◽  
Alessandro Paoletti
Keyword(s):  
Theoretical Approach ◽  
Rainfall Regime ◽  
Combined Sewer Overflows ◽  
Event Simulation ◽  
Numerical Assessment ◽  
Combined Sewer ◽  
On Line ◽  
Sewer Overflows ◽  
Two Parameters

The paper describes a theoretical analysis and a numerical assessment of pollutant loads discharged from Combined Sewer Overflows (CSOs) - with or without stormwater tanks – into the environment. The theoretical approach was based on certain simple assumptions, reasonably valid if the time scale of the problem involved is long enough (month/ year), in that single-event simulation is not interesting at all. Two main parameters related to the rainfall regime were found to be significant: the total volume of water discharged from the structure and the effective mixing factor between sanitary sewage and storm runoff. A numerical assessment of these two parameters was then made, on an annual basis, by means of a long-term rainfall series recorded in Milan, Italy. Both the “simple” CSO structure and the CSO coupled with stormwater tanks (on-line or off-line) were considered. The resulting graphs make it possible to evaluate the total annual load discharged from CSOs into the environment and the potential reduction obtained by adding a storage capacity to the overflow. This estimation could be of interest for persistent pollutants (phosphorus, heavy metals) discharged into low-recirculation bodies (lakes, estuaries, lagoons, closed seas).

scholarly journals The Role of Sewer Network Structure on the Occurrence and Magnitude of Combined Sewer Overflows (CSOs)

Water ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2675
Author(s):  
Julian Reyes-Silva ◽  
Emmanuel Bangura ◽  
Björn Helm ◽  
Jakob Benisch ◽  
Peter Krebs
Keyword(s):  
Network Structure ◽  
Mitigation Strategies ◽  
Mitigation Measures ◽  
Storm Events ◽  
Combined Sewer Overflows ◽  
Untreated Wastewater ◽  
Intense Storm ◽  
Combined Sewer ◽  
Sewer Overflows

Combined sewer overflows (CSOs) prevent surges in sewer networks by releasing untreated wastewater into nearby water bodies during intense storm events. CSOs can have acute and detrimental impacts on the environment and thus need to be managed. Although several gray, green and hybrid CSO mitigation measures have been studied, the influence of network structure on CSO occurrence is not yet systematically evaluated. This study focuses on evaluating how the variation of urban drainage network structure affects the frequency and magnitude of CSO events. As a study case, a sewer subnetwork in Dresden, Germany, where 11 CSOs are present, was selected. Scenarios corresponding to the structures with the lowest and with the highest number of possible connected pipes, are developed and evaluated using long-term hydrodynamic simulation. Results indicate that more meshed structures are associated to a decrease on the occurrence and magnitude of CSO. Event frequency reductions vary between 0% and 68%, while reduction of annual mean volumes and annual mean loads ranged between 0% and 87% and 0% and 92%. These rates were mainly related to the additional sewer storage capacity provided in the more meshed scenarios, following a sigmoidal behavior. However, increasing network connections causes investment costs, therefore optimization strategies for selecting intervention areas are needed. Furthermore, the present approach of reducing CSO frequency may provide a new gray solution that can be integrated in the development of hybrid mitigation strategies for the CSO management.

scholarly journals Maximizing Green Infrastructure in a Philadelphia Neighborhood

2017 ◽  
Vol 2 (4) ◽  
pp. 115-132 ◽  
Author(s):  
Kate Zidar ◽  
Timothy A. Bartrand ◽  
Charles H. Loomis ◽  
Chariss A. McAfee ◽  
Juliet M. Geldi ◽  
...  
Keyword(s):  
Green Infrastructure ◽  
Model Simulation ◽  
Private Land ◽  
Combined Sewer Overflows ◽  
Agent Based ◽  
Residential Neighborhood ◽  
Community Stakeholders ◽  
Combined Sewer ◽  
Green Stormwater Infrastructure

While the Philadelphia Water Department (PWD) is counting on Green Stormwater Infrastructure (GI) as a key component of its long-term plan for reducing combined sewer overflows, many community stakeholders are also hoping that investment in greening can help meet other ancillary goals, collectively referred to as sustainable redevelopment. This study investigates the challenges associated with implementation of GI in Point Breeze, a residential neighborhood of South Philadelphia. The project team performed a detailed study of physical, social, legal, and economic conditions in the pilot neighborhood over the course of several years, culminating in the development of an agent-based model simulation of GI implementation. The model evaluates a) whether PWD’s GI goals can be met in a timely manner, b) what kinds of assumptions regarding participation would be needed under different theoretical GI policies, and c) the extent to which GI could promote sustainable redevelopment. The model outcomes underscore the importance of private land in helping PWD achieve its GI goals in Point Breeze. Achieving a meaningful density of GI in the neighborhoods most in need of sustainable redevelopment may require new and creative strategies for GI implementation tailored for the types of land present in those particular communities.

scholarly journals Characterization of groundwater dynamics in landslides in varved clays

2013 ◽  
Vol 10 (1) ◽  
pp. 295-324 ◽  
Author(s):  
J. E. van der Spek ◽  
T. A. Bogaard ◽  
M. Bakker
Keyword(s):  
Boussinesq Equation ◽  
Richards Equation ◽  
Physical Parameters ◽  
Reservoir Model ◽  
Monitoring Point ◽  
Detailed Model ◽  
Groundwater Dynamics ◽  
Clay Layers ◽  
Linear Reservoir

Abstract. Groundwater dynamics may play a significant role in landslides. A detailed model is developed of the groundwater dynamics in landslides in varved clays in the Trièves area in the French Alps. The varved clays consist of a sequence of alternating silt and clay layers, covered by a colluvium layer and cut through by fissures. The hydraulic conductivity of the clay layers is negligible compared to the silt layers. It is conceptualized that fissures form a hydraulic connection between the colluvium and the varved clays. Groundwater recharge flows through the colluvium into the fissures where water is exchanged horizontally between the fissure and the silt layers of the varved clays. Groundwater flow in the colluvium is simulated with the Boussinesq equation while flow in the silt layers of the varved clays is simulated with the Richards' equation. Longitudinal outflow from the fissure is simulated with a linear-reservoir model. Scattered data of relatively short monitoring periods is available for several landslides in the region. A good similarity between observed and simulated heads is obtained, especially when considering the lack of important physical parameters such as the fissure width and the distance between the monitoring point and the fissure. A simulation for the period 1959–2004 showed some correlation between peaks in the simulated heads and the recorded occurrence of landslides while the bottom of the varved clays remained saturated during the entire simulation period.

scholarly journals Characterization of groundwater dynamics in landslides in varved clays

2013 ◽  
Vol 17 (6) ◽  
pp. 2171-2183 ◽  
Author(s):  
J. E. van der Spek ◽  
T. A. Bogaard ◽  
M. Bakker
Keyword(s):  
Boussinesq Equation ◽  
Richards Equation ◽  
Physical Parameters ◽  
Reservoir Model ◽  
Monitoring Point ◽  
Detailed Model ◽  
Groundwater Dynamics ◽  
Clay Layers ◽  
Linear Reservoir

Abstract. Groundwater dynamics may play a significant role in landslides. A detailed model is developed of the groundwater dynamics in landslides in varved clays in the Trièves area in the French Alps. The varved clays consist of a sequence of alternating silt and clay layers, covered by a colluvium layer and intersected by fissures. The hydraulic conductivity of the clay layers is negligible compared to the silt layers. It is conceptualized that fissures form a hydraulic connection between the colluvium and the varved clays. Groundwater recharge flows through the colluvium into the fissures, where water is exchanged horizontally between the fissure and the silt layers of the varved clays. Groundwater flow in the colluvium is simulated with the Boussinesq equation, while flow in the silt layers of the varved clays is simulated with the Richards equation. Longitudinal outflow from the fissure is simulated with a linear-reservoir model. Scattered data of relatively short monitoring periods is available for several landslides in the region. A good similarity between observed and simulated heads is obtained, especially when considering the lack of important physical parameters such as the fissure width and the distance between the monitoring point and the fissure. A simulation for the period 1959–2004 showed some correlation between peaks in the simulated heads and the recorded occurrence of landslides, while the bottom of the varved clays remained saturated during the entire simulation period.

scholarly journals Analytical River Routing with Alternative Methods to Estimate Seepage

2019 ◽  
pp. 167-192
Author(s):  
Hubert J. Morel-Seytoux
Keyword(s):  
River Flow ◽  
Alternative Methods ◽  
Accurate Estimation ◽  
Adjacent Cell ◽  
Reservoir Model ◽  
River Stage ◽  
Physically Based ◽  
Linear Reservoir ◽  
River Routing

Knowledge of flow exchange between surface and groundwater is of great importance for use of water resources. The determination of seepage between a stream and an underlying aquifer requires an accurate estimation of the river stage and of the head in the aquifer. An approach is presented to estimate analytically river flow and stage while using the SAFE conductance to calculate the seepage.  A major contribution of this article lies in the methodology for river routing with its use of a modified Linear Reservoir model.  The parameter C is related to discharge based on Manning’s equation. That relation breathes into an empirical model a dynamic character. A second major contribution is to show that it is possible to simultaneously calculate river stage and aquifer head in the aquifer cell that contains the river.  As a result iteration is not necessary to estimate that river cell head as river stage changes, as opposed to what is usually done in most numerical groundwater models.  Iteration is still needed for the adjacent cells to the river cell.  Because the influence of a change in the adjacent cell head on the river cell head is much delayed and attenuated the iteration is not sensitive to that change. A goal of this document is to show how that method can be used within a simple physically based routing procedure [1] to estimate the river stage that has a definite influence on seepage.

Urban Storm Water Discharges: Effects upon Communities of Sessile Diatoms and Macro-Invertebrates

1990 ◽  
Vol 22 (10-11) ◽  
pp. 147-154 ◽  
Author(s):  
G. D. Willemsen ◽  
H. F. Gast ◽  
R. O. G. Franken ◽  
J. G. M. Cuppen
Keyword(s):  
Organic Pollution ◽  
Constant Flow ◽  
Combined Sewer Overflows ◽  
Sewer System ◽  
Sewer Systems ◽  
Combined Sewer ◽  
Receiving Waters ◽  
Sewer Overflows ◽  
Urban Storm

From 1985 to 1987, long-term and more or less permanent effects of discharges from combined or separate sewer systems on communities of sessile diatoms and macro-invertebrates in receiving waters have been studied. Sessile diatoms and/or macro-invertebrates have been investigated on 46 locations, spread all over The Netherlands. The results were related to the type of sewer system, the discharges, and the characteristics of the receiving water, and compared with results from sample(s) taken from a corresponding water not influenced by sewer overflows, the reference water. In general, communities of sessile diatoms and macro-invertebrates indicate a more severe organic pollution and disturbance of receiving waters compared with reference waters. In the immediate vicinity of the overflows these communities were more disturbed than at some distance. In small ditches, effects were more pronounced compared with large waterbodies and waters with a constant flow regime. Finally, effects of combined sewer overflows were more pronounced than effects of discharges from separate sewer systems, except for locations in industrial areas.

Modeling climate change impacts on combined sewer overflow using synthetic precipitation time series

2013 ◽  
Vol 68 (1) ◽  
pp. 160-166 ◽  
Author(s):  
David Bendel ◽  
Ferdinand Beck ◽  
Ulrich Dittmer
Keyword(s):  
Climate Change ◽  
Time Series ◽  
Climate Change Impacts ◽  
Rainfall Time Series ◽  
Combined Sewer Overflows ◽  
Precipitation Time Series ◽  
Climate Change Effects ◽  
Combined Sewer ◽  
Synthetic Precipitation

In the presented study climate change impacts on combined sewer overflows (CSOs) in Baden-Wuerttemberg, Southern Germany, were assessed based on continuous long-term rainfall–runoff simulations. As input data, synthetic rainfall time series were used. The applied precipitation generator NiedSim-Klima accounts for climate change effects on precipitation patterns. Time series for the past (1961–1990) and future (2041–2050) were generated for various locations. Comparing the simulated CSO activity of both periods we observe significantly higher overflow frequencies for the future. Changes in overflow volume and overflow duration depend on the type of overflow structure. Both values will increase at simple CSO structures that merely divide the flow, whereas they will decrease when the CSO structure is combined with a storage tank. However, there is a wide variation between the results of different precipitation time series (representative for different locations).

CSO Modelling Considering Moving Storms and Tipping Bucket Gauge Failures

2007 ◽  
Vol 2 (1) ◽  
Author(s):  
M. Hochedlinger ◽  
W. Sprung ◽  
H. Kainz ◽  
K. König
Keyword(s):  
Hydrological Models ◽  
Rain Intensity ◽  
Hydrodynamic Models ◽  
Data Intensive ◽  
Storm Flow ◽  
Cell Velocity ◽  
Combined Sewer ◽  
Moving Direction ◽  
The Difference

The simulation of combined sewer overflow volumes and loads is important for the assessment of the overflow and overflow load to the receiving water to predict the hydraulic or the pollution impact. Hydrodynamic models are very data-intensive and time-consuming for long-term quality modelling. Hence, for long-term modelling, hydrological models are used to predict the storm flow in a fast way. However, in most cases, a constant rain intensity is used as load for the simulation, but in practice even for small catchments rain occurs in rain cells, which are not constant over the whole catchment area. This paper presents the results of quality modelling considering moving storms depending on the rain cell velocity and its moving direction. Additionally, tipping bucket gauge failures and different corrections are also taken into account. The results evidence the importance of these considerations for precipitation due the effects on overflow load and show the difference up to 28% of corrected and uncorrected data and of moving rain cells instead of constant raining intensities.

Implementation of Hamilton-Wentworth Region’s Pollution Control Plan

1996 ◽  
Vol 31 (3) ◽  
pp. 453-472 ◽  
Author(s):  
M. Stirrup
Keyword(s):  
Wastewater Treatment ◽  
Pollution Control ◽  
Wastewater Treatment Plant ◽  
Treatment Plant ◽  
Control Measures ◽  
Storm Events ◽  
Combined Sewer Overflows ◽  
Control Plan ◽  
Combined Sewer ◽  
Sewer Overflows

Abstract The Regional Municipality of Hamilton-Wentworth operates a large combined sewer system which diverts excess combined sewage to local receiving waters at over 20 locations. On average, there are approximately 23 combined sewer overflows per year, per outfall. The region’s Pollution Control Plan, adopted by Regional Council in 1992, concluded that the only reasonable means of dealing with large volumes of combined sewer overflow in Hamilton was to intercept it at the outlets, detain it and convey it to the wastewater treatment plant after the storm events. The recommended control strategy relies heavily on off-line storage, with an associated expansion of the Woodward Avenue wastewater treatment plant to achieve target reductions of combined sewer overflows to 1–4 per year on average. The region has begun to implement this Pollution Control Plan in earnest. Three off-line detention storage tanks are already in operation, construction of a fourth facility is well underway, and conceptual design of a number of other proposed facilities has commenced. To make the best possible use of these facilities and existing in-line storage, the region is implementing a microcomputer-based real-time control system. A number of proposed Woodward Avenue wastewater treatment plant process upgrades and expansions have also been undertaken. This paper reviews the region's progress in implementing these control measures.

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