Heinz Erasmus Jacobs

Heinz Erasmus Jacobs
Stellenbosch University | SUN · Department of Civil Engineering

PhD (Civil Engineering)

About

63
Publications
14,538
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
475
Citations
Introduction
HEINZ JACOBS is an Associate Professor at Stellenbosch University with 27 years civil engineering experience. The focus of his work is water demand modelling, water conservation and water services planning.
Additional affiliations
January 2006 - present
Stellenbosch University
Position
  • Professor (Associate)

Publications

Publications (63)
Article
Full-text available
This research investigated relationships between the most notable characteristics of end-use events, namely, event duration, volume, and intensity, in order to categorize water use as being indoor or outdoor. Three classification models were developed, calibrated, and compared using more than 200,000 household end-use events that were recorded inde...
Article
Full-text available
As the world increasingly faces water shortages, it is critical to develop realistic estimates of water consumption based on water-use activities rather than top-down imposed limits. This study quantifies the absolute basic consumption (ABC) of an individual, irrespective of water-use location or water source, with a focus on personal water-use act...
Article
Full-text available
Distinguishing between indoor use and outdoor use is becoming increasingly important, especially in water-scarce regions, since outdoor use is typically targeted during water restrictions. Household water use is typically measured at a single water meter, and the resolution of the metered data is typically too coarse to employ on commercially avail...
Article
Full-text available
The prevalence of intermittent water supply in South Africa was investigated in this research study. Data on intermittent water supply in South Africa was collated by considering the following four sources: a targeted water services provider survey; published databases and related reports; open-access publications, such as online media articles; an...
Article
Household water end-uses have been extracted from high-resolution smart water meter data in various earlier studies. However, research on end-use disaggregation from rudimentary data is limited. Rudimentary data is defined as data recorded in intervals longer than 1 min, or data recorded with resolutions larger than 0.1 L/pulse. Developing countrie...
Article
Full-text available
Gated community homes in South Africa are popular amongst property buyers in urban environments such as cities and metropoles due to the increased security and lifestyle improvements offered. Garden design and layout requirements are prescribed in architectural guidelines compiled by the homeowners associations of these communities. Garden footprin...
Article
Full-text available
Water temperature is often monitored at water sources and treatment works; however, there is limited monitoring of the water temperature in the drinking water distribution system (DWDS), despite a known impact on physical, chemical and microbial reactions which impact water quality. A key parameter influencing drinking water temperature is soil tem...
Article
Full-text available
Various challenges, such as limited freshwater resources, climate change impacts, rapid population growth, urbanisation and underinvestment in water supply infrastructure, have led to intermittent water supply (IWS) in potable water distribution systems. Earlier research has confirmed that IWS negatively impacts the consumers, the infrastructure an...
Article
Full-text available
A novel method for baseline adjustment in a shared water savings contract under serious drought conditions was presented in a companion paper. The newly developed baseline adjustment method was subsequently applied to a case study, as discussed in this manuscript. The case study involved application of the method to 24 relatively complex sites, spr...
Article
Full-text available
Baselines are often employed in shared water saving contracts for estimating water savings after some type of intervention by the water service company. An adjustment to the baseline may become necessary under certain conditions. Earlier work has described a number of relatively complex methods for baseline determination and adjustment, but applica...
Article
Untreated greywater reuse at the household level is an accessible water source to supplement non-potable water requirements in times of emergency water curtailments but poses various risks to the consumer, the wider community, infrastructure and the environment. Little is known about unregulated, untreated greywater reuse practices under emergency...
Article
Full-text available
Garden irrigation is a significant and variable household water end‑use, while groundwater abstraction may be a notable supplementary water source available in some serviced residential areas. Residential groundwater is abstracted by means of garden boreholes or well points and – in the study area – abstracted groundwater is typically used for gard...
Article
The diurnal water use patterns are of interest to hydraulic modellers, as these patterns are required for the design of water distribution systems. An extensive body of literature is available with regard to daily, weekly and seasonal diurnal water use patterns of typical suburban houses. However, the characteristics of South African low-cost house...
Article
The effect of pressure adjustments on individual consumer water demand is presented in this paper. The study involved collecting and analysing data from two sites in an operational water reticulation system in South Africa. Pressures and flow rates were monitored at a few strategic locations and at 44 individual homes during a series of controlled...
Article
Disaggregating residential water use into components for indoor and outdoor use is useful in view of water services planning and demand management campaigns, where outdoor use is often the target of water restrictions. Previous research has shown that individual end-use events can be identified based on analysis of the flow pattern at the water met...
Article
Full-text available
Gated communities (hereafter GCs) are popular in many countries, including South Africa, because added security and lifestyle improvements are offered relative to homes built on freestanding properties. One of the key factors for the popularity of GCs is the availability of amenities to support the demands of the residents, such as gymnasia, walkwa...
Article
Full-text available
This paper addresses on-site supplementary household water sources with a focus on groundwater abstraction, rainwater harvesting and greywater reuse as available non-potable water sources to residential consumers. An end-use model is presented and used to assess the theoretical impact of household water sources on potable water demand in formal res...
Article
In this study, panel linear models were used to develop an empirical relationship between metered household water use and the independent variables plot size and theoretical irrigation requirement. The estimated statistical model provides a means of estimating the climate-sensitive component of residential water use. Ensemble averages of temperatur...
Article
Full-text available
Sub-standard residual water pressures in urban water distribution systems (WDS) are a prevalent phenomenon in developing countries – South Africa being no exception. The phenomenon of sub-standard pressure is poorly understood, with intermittent supply ultimately resulting when there is no residual pressure left in the system. This research address...
Article
Full-text available
Obtaining disaggregated water use at the home typically involves expensive smart metering. In this study, water use events at the outdoor tap were captured using recorded sound. Outdoor taps at 10 homes were fitted with small-sized microphones and digital sound recorders. Sound files recorded over a 1-month period were used in the analysis. In the...
Article
Malawi has one of the highest urbanisation rates in Africa, with an urban housing approach that favours large residential plot sizes. The impact of plot size on residential water use was evaluated by examining water use records, obtained for the period between January 2009 and December 2014, for formal residential properties in the city of Lilongwe...
Article
Full-text available
The potable water use recorded by 3 579 residential consumer water meters in Cape Town, South Africa, was analysed as part of this research. The focus was on selected residential properties in serviced areas, with additional private access to groundwater as a supplementary household water source. Private consumers in South Africa are not normally r...
Article
Full-text available
The outdoor water use of residential properties is a major contributor to the seasonal fluctuation of the overall water use of these properties. The outdoor water use components were mathematically defined and combined to develop an outdoor water use model. The parameters that formed part of the mathematical outdoor water use model were formulated...
Article
Southern Africa is likely to experience higher evapotranspiration and altered rainfall characteristics due to global warming and climate change. Climate-driven water use may potentially stress water supply facilities due to increased demand and reduced surface water yield. This paper presents a conceptual theoretical framework for assessing impacts...
Article
Southern Africa is likely to experience higher evapotranspiration and altered rainfall characteristics due to global warming and climate change. Climate-driven water use may potentially stress water supply facilities due to increased demand and reduced surface water yield. This paper presents a conceptual theoretical framework for assessing impacts...
Conference Paper
Full-text available
Laboratory tests were carried out to record the sound of water flowing through a tap and the corresponding flow rate. The results were analysed to determine a mathematical relationship between the sound signal and the flow rate. Three models, based on Fourier transforms of data in the frequency domain, were devised to estimate the flow rate of wate...
Article
Full-text available
Sewer pump station problems in separate sewer systems (separate from stormwater drainage systems) were investigated in order to derive a conceptual framework for decision making. Notwithstanding the fundamental service that efficient sewage pumping provides to a community, it was apparent that limited research has been published on the topic. Resea...
Article
Full-text available
In October 2004 the City of Cape Town implemented water restrictions in line with the city's holistic approach to water demand management. To better understand the savings and improve the effectiveness of future restrictions, a detailed demand analysis was conducted during this period. In this paper the authors report on various aspects pertaining...
Article
Full-text available
A probability based end-use model was constructed as part of this study to derive diurnal residential indoor water demand patterns on a temporal scale of 10 seconds. The end-use model derived the water demand patterns by aggregating the synthesised end-use events of six residential indoor enduses of water in terms of the water volume required, dura...
Article
Full-text available
A probability based end-use model was constructed as part of this study to derive diurnal residential indoor water demand patterns on a temporal scale of 10 seconds. The end-use model derived the water demand patterns by aggregating the synthesised end-use events of six residential indoor end-uses of water in terms of the water volume required, dur...
Conference Paper
Full-text available
The outdoor water consumption of residential properties is a major contributor to the seasonal fluctuation of water demand. An outdoor water demand estimation model is presented where water-use components were mathematically defined and combined to develop an outdoor water demand model. The model input parameters were formulated from data available...
Article
Full-text available
Alternative methods of firefighting and new firefighting technologies could reduce the reliance on potable water supplied via the water distribution system (WDS) for firefighting. Water required for firefighting in 5 towns in proximity to Stellenbosch, South Africa, was evaluated. The key objective of this research project was to investigate the ex...
Article
Full-text available
The implementation of water conservation and water demand management (WC/WDM) at municipal level has been inadequate for many years, despite South Africa being one of the driest countries in the world. This could be attributed to a lack of planning, and not realising the consequences and potential benefits of water restrictions. Many South African...
Article
Full-text available
Background: Information aggregation to suburb level is of interest to engineers and urban planners. Readily available suburb boundaries do not always correspond to the suburb names recorded for individual properties in different data bases and unwanted errors are inherent. This mismatch of suburb names at different spatial scales poses a particular...
Article
Full-text available
Current guidelines for estimating the average annual residential water demand (AADD) in South Africa are based on residential plot size. This paper presents a novel, robust method for estimating suburban water demand as a function of the suburb area. Seventy suburbs, identified as being predominantly residential, were selected for analysis from the...
Article
Full-text available
Background: Water service providers invoice most South African urban consumers for the water they use every month. A secure treasury system generates water invoices at municipalities’ financial departments. Information about the water usage of customers initially comes from reading the water meters, usually located in gardens near the front boundar...
Technical Report
Full-text available
Background Water resource managers, water demand managers and water infrastructure planners alike, are faced with an acute lack of knowledge regarding on-site household water use as additional water source to potable Municipal supply. The most common on-site household water sources (HWS) of this nature include:  groundwater abstraction by means of...
Conference Paper
Full-text available
Groundwater abstraction at serviced residential properties (via boreholes, well points, shallow wells, fountains or springs) for gardening in the Cape Peninsula is a reality. The extent thereof as well as the effect it has on municipal (potable) water use in the Cape Peninsula has not been investigated before. The first step of this study was to id...
Conference Paper
Full-text available
Groundwater abstraction at serviced residential properties (via boreholes, well points, shallow wells, fountains or springs) for gardening in the Cape Peninsula is a reality. The extent thereof as well as the effect it has on municipal (potable) water use in the Cape Peninsula has not been investigated before. The first step of this study was to id...
Conference Paper
The researchers report on an extensive survey of South African guidelines for sewer network design and analysis and identify the current regional philosophies for system master planning. In order to streamline the master planning process in South Africa and develop a best management procedure a three tier philosophy is proposed by the authors for s...
Article
Full-text available
The Water Institute of Southern Africa (WISA) held its first conference in 1989 in Cape Town. The most recent and 10 th Biennial WISA Conference was held in May 2008 at Sun City, South Africa. The WISA 2008 conference theme, 'Conflu-ence of the Water Industry' set the scene for a wide range of presentations with regards to the South African water i...
Article
Full-text available
The South African civil engineering fraternity has grown to accept 24 m as the design criterion for minimum residual pressure in water distribution systems. However, the theoretical peak demand in many systems has increased beyond the point where minimum residual pressure exceeds 24 m – at least according to hydraulic models. Additions of customers...
Article
Full-text available
Guidelines for residential average annual water demand (AADD) based on property size were introduced to the South African Civil Engineering fraternity in about 1960, with the most recent publication of such guidelines in 2008. The AADD forms the basis of calculations performed during the design and analysis of water systems. Over the years technolo...
Article
A residential end use model (REUM) which accounts for indoor water demand, outdoor water demand, hot water demand, wastewater flow and the mass of total dissolved substances (TDS) In the wastewater, was earlier described by the authors. The integral relationship between water quality and quantity in the model allows for holistic modelling of differ...
Article
Full-text available
End-use modelling of residential water demand is becoming increasingly relevant. It encourages better understanding of how water is used by end users. Such an understanding is invaluable in view of improved water use efficiency and savings. This paper reports on the practical application of end-use modelling. The sample correlation between end-use-...
Article
Full-text available
Answers were obtained from a carefully designed questionnaire and then used as input in an end-use water demand model for analysis of residential water demand. The results could be verified by comparing it to actual metered data from the utility billing system. The initial evaluation comprised the distribution and completion of questionnaires by ha...
Article
Full-text available
The question in the title of this paper is fundamental to each household in South Africa accepting responsibility for its water demand. The researchers applied an end-use model to estimate water demand at 11 individual residential properties as part of a pilot study. The work was extended to include another 149 properties. The inputs for the model...
Article
Full-text available
The structure and data requirements of an end-use model for residential water demand and return flow are presented in a companion paper. This paper focuses on the practical application of the model. The model is first applied to confirm a few commonly observed water demand patterns: Seasonal variation in demand, the positive correlation between ave...
Article
Full-text available
An end-use model for residential water demand and return flow is presented in this paper. The model requires a unique description of a single residential stand in terms of all its end-uses. The end-uses include toilet flushing, bathing and showering, garden watering, pool water use, leaks, et cetera. Various parameters describe each of the end-uses...
Article
Full-text available
The relationship between water demand, wastewater flow and the addition of household pollutants (detergents, human and kitchen waste, etc.) for a single residential stand is investigated. The researchers apply a conceptual end-use model for water demand and wastewater flow to investigate these characteristics. The power of an end-use model lies in...
Article
Full-text available
It is understandable that an easy method to obtain estimates of residential water demand is often used. These estimates are also extended to calculate peak demand and sewer flow, and impact an authority’s water and sewer infrastructure budget and finally its expenditure. Guideline curves are presented in this paper that can be used to estimate annu...
Article
It is understandable that an easy method to obtain estimates of residential water demand is often used. These estimates are also extended to calculate peak demand and sewer flow, and impact an authority's water and sewer infrastructure budget and finally its expenditure. Guideline curves are presented in this paper that can be used to estimate annu...
Article
Full-text available
Grey water – wastewater from the bath, shower and washing machine – is available to all residential water users as a personal, on-site water resource (P O S W A R) . Despite contradicting reports on the value versus danger of on-site reuse, grey water constitutes a significant fraction (± 50%) of wastewater flow from a typical suburban home, where...
Article
Full-text available
Methods for estimating non-domestic water demand are often based on out-dated methods, merely because these older guidelines are practical and easy to use. Most of these existing guidelines group the non-domestic user types into generalized categories, not providing a diversified data range. Experience has shown that these guidelines are also conse...
Article
Full-text available
It is necessary to construct a detailed end-use water demand model of a dwelling to estimate the potential effects of specific water demand management measures on water demand. These models estimate the water demand at every water using node (such as taps, baths, gardens, et cetera) and are therefore very detailed with a great number of input param...
Article
Full-text available
In a developing nation such as South Africa, with its mix of first and third world service levels, effective sewer and water master planning is vital. However, as backlogs are identified and services are provided the sewer master plans are in need of regular updating. In this continuously evolving system the challenge has been to maintain the accur...
Article
Full-text available
Infrastructure costs are a crucial part of sewer system master planning, since the unit costs are needed during the optimisation stages of the analysis. Therefore it is of paramount importance, in the preliminary stages of a project, to have relatively accurate estimates of the infrastructure cost. The item cost for previous projects across South-A...
Article
Full-text available
A personal on-site water resource (POSWAR) is an alternative water source to piped municipal supply. POSWARs are available to all residential consumers in South Africa and include groundwater abstraction, rainwater harvesting and greywater reuse. POSWARs are commonly applied to meet garden irrigation demand, where water quality issues are often not...

Questions

Question (1)
Question
We are busy with a study in Cape Town, South Africa, to better understand the impact of private groundwater use on the WDS demand and would like to compare our results to findings elsewhere. In our area groundwater is normally non-potable and is used for garden watering, mainly in the peak (dry) season.

Network

Cited By

Projects

Projects (2)
Project
Intermittent Water Supply (IWS) is the practise of supplying water in piped networks for limited periods, less than 24 hours per day (continuous supply). This means of network operation causes accelerated infrastructure deterioration, water quality degradation and social inequalities. This project investigates the filling cycle of IWS and how related hydraulic parameters influence the dynamic flows and pressures induced. Extensive laboratory experiments and field work in South Africa were performed as part of a collaboration with Stellenbosch University. This work was funded by the Newton Fund Industry Academic Partnership Programme IAPP1R2\100207.