scholarly journals A bottom-up approach of stochastic demand allocation in a hydraulic network model: a sensitivity study of model parameters

2011 ◽  
Vol 13 (4) ◽  
pp. 714-728 ◽  
Author(s):  
E. J. M. Blokker ◽  
H. Beverloo ◽  
A. J. Vogelaar ◽  
J. H. G. Vreeburg ◽  
J. C. van Dijk
Keyword(s):  
Water Demand ◽  
Spatial Aggregation ◽  
Model Parameters ◽  
Residence Times ◽  
Time Step ◽  
Bottom Up ◽  
Demand Pattern ◽  
Demand Patterns ◽  
Water Demand Patterns ◽  
Demand Allocation

An “all pipes” hydraulic model of a drinking water distribution system was constructed with a bottom-up approach of demand allocation. This means that each individual home is represented by one demand node with its own stochastic water demand pattern. These water demand patterns were constructed with the end-use model SIMDEUM. A sensitivity test with respect to the resulting residence times was performed for several model parameters: time step, spatial aggregation, spatial correlation, demand pattern and number of simulation runs. The bottom-up approach of demand allocation was also compared to the conventional top-down approach, i.e. a single demand multiplier pattern is allocated to all demand nodes with the base demand to account for the average water demand on that node. The models were compared to measured flows and residence times in a small network. The study showed that the bottom-up approach leads to realistic water demand patterns and residence times, without the need for any flow measurements. The stochastic approach of hydraulic modelling, with a 15 minute time step, some spatial aggregation and 10 simulation runs, gives insight into the variability of residence times as an added feature beyond the conventional way of modelling.

scholarly journals A bottom-up approach of stochastic demand allocation in water quality modelling

2010 ◽  
Vol 3 (1) ◽  
pp. 43-51 ◽  
Author(s):  
E. J. M. Blokker ◽  
J. H. G. Vreeburg ◽  
H. Beverloo ◽  
M. Klein Arfman ◽  
J. C. van Dijk
Keyword(s):  
Drinking Water ◽  
Water Demand ◽  
Distribution System ◽  
Water Distribution ◽  
Water Distribution System ◽  
Drinking Water Distribution System ◽  
Travel Times ◽  
Bottom Up ◽  
Drinking Water Distribution ◽  
Demand Patterns

Abstract. An "all pipes" hydraulic model of a drinking water distribution system was constructed with two types of demand allocations. One is constructed with the conventional top-down approach, i.e. a demand multiplier pattern from the booster station is allocated to all demand nodes with a correction factor to account for the average water demand on that node. The other is constructed with a bottom-up approach of demand allocation, i.e., each individual home is represented by one demand node with its own stochastic water demand pattern. This was done for a drinking water distribution system of approximately 10 km of mains and serving ca. 1000 homes. The system was tested in a real life situation. The stochastic water demand patterns were constructed with the end-use model SIMDEUM on a per second basis and per individual home. Before applying the demand patterns in a network model, some temporal aggregation was done. The flow entering the test area was measured and a tracer test with sodium chloride was performed to determine travel times. The two models were validated on the total sum of demands and on travel times. The study showed that the bottom-up approach leads to realistic water demand patterns and travel times, without the need for any flow measurements or calibration. In the periphery of the drinking water distribution system it is not possible to calibrate models on pressure, because head losses are too low. The study shows that in the periphery it is also difficult to calibrate on water quality (e.g. with tracer measurements), as a consequence of the high variability between days. The stochastic approach of hydraulic modelling gives insight into the variability of travel times as an added feature beyond the conventional way of modelling.

scholarly journals A bottom-up approach of stochastic demand allocation in water quality modelling

2010 ◽  
Vol 3 (1) ◽  
pp. 1-24
Author(s):  
E. J. M. Blokker ◽  
J. H. G. Vreeburg ◽  
H. Beverloo ◽  
M. Klein Arfman ◽  
J. C. van Dijk
Keyword(s):  
Water Demand ◽  
Distribution System ◽  
Water Distribution ◽  
Test Area ◽  
Travel Times ◽  
Top Down ◽  
Flow Measurements ◽  
Bottom Up ◽  
Demand Node ◽  
Demand Allocation

Abstract. An "all pipes" hydraulic model of a DMA-sized drinking water distribution system was constructed with two types of demand allocations. One is constructed with the conventional top-down approach, i.e. a demand multiplier pattern from the booster station is allocated to all demand nodes with a correction factor to account for the average water demand on that node. The other is constructed with a bottom-up approach of demand allocation, i.e., each individual home is represented by one demand node with its own stochastic water demand pattern. The stochastic water demand patterns are constructed with an end-use model on a per second basis and per individual home. The flow entering the test area was measured and a tracer test with sodium chloride was performed to measure travel times. The two models were evaluated on the predicted sum of demands and travel times, compared with what was measured in the test area. The new bottom-up approach performs at least as well as the conventional top-down approach with respect to total demand and travel times, without the need for any flow measurements or calibration measurements. The bottom-up approach leads to a stochastic method of hydraulic modelling and gives insight into the variability of travel times as an added feature beyond the conventional way of modelling.

scholarly journals Comparison of Bottom-Up and Top-Down Procedures for Water Demand Reconstruction

Water ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 922 ◽  
Author(s):  
Diana Fiorillo ◽  
Enrico Creaco ◽  
Francesco De Paola ◽  
Maurizio Giugni
Keyword(s):  
Time Series ◽  
Water Demand ◽  
Second Phase ◽  
Top Down ◽  
Shift Parameter ◽  
Time Step ◽  
Bottom Up ◽  
Smart Water ◽  
Cross Correlations ◽  
Two Phases

This paper presents a comparison between two procedures for the generation of water demand time series at both single user and nodal scales, a top-down and a bottom-up procedure respectively. Both procedures are made up of two phases. The top-down procedure adopted includes a non-parametric disaggregation based on the K-nearest neighbours approach. Therefore, once the temporal aggregated water demand patterns have been defined (first phase), the disaggregation is used to generate water demand time series at lower levels of spatial aggregation (second phase). In the bottom-up procedure adopted, demand time series for each user and for each time step are generated applying a beta probability distribution with tunable bounds or a gamma distribution with shift parameter (first phase). Then, a Copula based re-sort is applied to the demand time series generated to impose existing rank cross-correlations between users and at all temporal lags (second phase). For the sake of comparison, two case studies were considered, both of which are related to a smart water network in Naples (Italy). The results obtained show that the bottom-up procedure performs significantly better than the top-down procedure in terms of rank-cross correlations at fine scale. However, the top-down procedure showed a better performance in terms of skewness and rank cross-correlation when the aggregated demands were considered. Finally, the level of aggregation in nodes was found to affect the performance of both the procedures considered.

Changes in water demand patterns in a European city due to restrictions caused by the COVID-19 pandemic

2021 ◽  
Vol 222 ◽  
pp. 1-15
Author(s):  
Jan K. Kazak ◽  
Szymon Szewrański ◽  
Tomasz Pilawka ◽  
Katarzyna Tokarczyk-Dorociak ◽  
Kamil Janiak ◽  
...  
Keyword(s):  
Water Demand ◽  
European City ◽  
Demand Patterns ◽  
Water Demand Patterns

scholarly journals One or more water demand patterns? - Calibration of the selected water network model

2018 ◽  
Vol 59 ◽  
pp. 00020
Author(s):  
Beata Kowalska ◽  
Dariusz Kowalski ◽  
Paweł Suchorab ◽  
Małgorzata Iwanek
Keyword(s):  
Network Model ◽  
Water Demand ◽  
Optimization Method ◽  
Water Network ◽  
Supply Networks ◽  
Demand Pattern ◽  
Trial And Error Method ◽  
Key Steps ◽  
Demand Patterns ◽  
Error Method

Calibration is one of the key steps in creating a numerical model of water supply networks. Calibration is performed on the basis of the results of the field measurement campaign and it should result in a consistent match of the simulation results with the results of the measurements. In the article the process and the results of the calibration of the selected water network model with the use a single (generalized) water demand pattern and using 11 patterns prepared for selected, characteristic consumers have been presented. Calibration was performed using the trial and error method in EPANET 2.0 and the optimization method in WaterGEMS.

Sign in / Sign up

Export Citation Format

Share Document