HESRIV-489 Services Report -Rev 2enviro-eap.co.za/wp-content/uploads/2020/06/Appendix_L2... · 2020-06-25 · hessequa municipality services report for civil engineering services

HESSEQUA MUNICIPALITY

SERVICES REPORT

FOR CIVIL ENGINEERING SERVICES ON PORTION 111 OF

THE FARM MELKHOUTFONTEIN NO 480 FOR

HESSEQUA MUNICIPALITY

HESRIV-489

Revision 2.0

AUGUST 2019

PREPARED BY:

CLIENT:

ASLA DEVCO PO Box 118 GORDONS BAY 7151

MR G PEPLER 22 HEIDELBERG ROAD

RIVERSDALE 6670

Tel : (028) 713 4030 Fax : 086 617 4114

Mobile : 083 447 9297 Email : [email protected]

SERVICES REPORT FOR CIVIL ENGINEERING SERVICES ON PORTION 111 OF THE FARM MELKHOUTFONTEIN NO 480 FOR HESSEQUA MUNICIPALITY

DOCUMENT CONTROL

DATE REVISION COMMENT

21 January 2019 0 Civil Services Report for conditional approval

19 February 2019 1 Additional information with regard to the WWTW

12 August 2019 2 Additional information with regard to the WWTW and Traffic Impact Assessment


ABBREVIATIONS

AADD : Annual Average Daily Demand (water)

ADF : Average Daily Flow (sewage)

CES : Community Engineering Services

GLS : GSL Consulting Engineers

HM : Hessequa Municipality

ha : hectare

HCE : Hessequa Consulting Engineers CC

kℓ : kilolitre

kℓ/d : kilolitre per day

ℓ/c/d : kilolitre per capita per day

m : metres

masl : metres above mean sea level

MIG : Municipal Infrastructure Grant

Mℓ : mega litre

m3 : cubic metre, i.e. one kilolitre

mm : millimetre

TWL : Top of Water Level (Dam or Reservoir)

VAT : Value added tax

WTW : Water Treatment Works

WWTW : Waste Water Treatment Works


TABLE OF CONTENT

INTRODUCTION ........................................................................................................................................4

LOCATION AND ACCESS ........................................................................................................................4

CIVIL ENGINEERING SERVICES .............................................................................................................4

1.1 MASS EARTHWORKS ....................................................................................................................4

1.2 ACCESS ROAD ...............................................................................................................................5

1.3 INTERNAL ROADS ..........................................................................................................................5

1.4 STORMWATER ................................................................................................................................6

1.4.1 Major Systems ..............................................................................................................................6

1.4.2 Minor Systems and Storm water Design ......................................................................................6

1.5 WATER .............................................................................................................................................7

1.5.1 WATER SOURCE AND WTW ......................................................................................................7

3.5.2 WATER DEMAND ........................................................................................................................9

3.5.3 EXISTING STORAGE CAPACITY ...............................................................................................9

3.5.4 BULK WATER DISTRIBUTION ................................................................................................. 10

3.5.5 INTERNAL WATER RETICULATION........................................................................................ 10

3.6 SEWAGE TREATMENT AND SEWER MAINS ............................................................................ 10

3.6.1 WWTW ....................................................................................................................................... 10

3.6.2 SEWER MAINS ......................................................................................................................... 13

3.6.3 SEWER RETICULATION .......................................................................................................... 13

3.7 ELECTRICAL SLEEVES .............................................................................................................. 13

COST ESTIMATE : MELKHOUTFONTEIN HOUSING .......................................................................... 13

CONCLUSION ........................................................................................................................................ 15

ANNEXURE A : DRAWINGS ............................................................................................................... 16

HESRIV-489-BW-01 : BULK WATER LAYOUT .................................................................................. 16

HESRIV-489-BS-01 : BULK SEWER LAYOUT ................................................................................... 16

HESRIV-489-W01 : WATER RETICULATION TYPICAL DETAILS .................................................... 16

HESRIV-489-S01 : SEWER RETICULATION TYPICAL DETAILS ..................................................... 16

ANNEXURE B : TRAFFIC IMPACT ASSESSMENT ........................................................................... 17


ANNEXURE C : TECHNICAL REPORT FOR THE UPGRADING OF THE MELKHOUTFONTEIN WASTEWATER TREATMENT WORKS ................................................................................................ 18


HESRIV-489 SERVICES REPORT -REV 2

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INTRODUCTION

Hessequa Consulting Engineers have been appointed by ASLA Devco for the planning and design of

civil engineering services, on Portion 111 of the Farm Melkhoutfontein No 480, for a Low-Cost Housing

project in Melkhoutfontein in the Western Cape. This report is based on a desk top study and is compiled

on behalf of the Hessequa Municipality for submission to the Department of Human Settlements as part

of the project application for conditional approval of the housing development.

The report will discuss the design criteria and specifications which will apply to civil engineering services

required for the development.

LOCATION AND ACCESS

Melkhoutfontein falls within the demarcated boundaries of the Hessequa Municipality in the Western

Cape and is situated 335km East of Cape Town and 35km South East of Riversdale, the administrative

headquarters of the region. The proposed development site (Portion 111 of the Farm Melkhoutfontein

No 480) is a vacant area adjacent (South) to Divisional Road 1528 known as Suikerbos Road.

One access, from Divisional Road 1528, will be provided opposite an existing intersection to the

Melkhoutfontein Industrial Area.

CIVIL ENGINEERING SERVICES

Proposed designs are based on the design standards of the Guidelines for the Provision of Engineering

Services and Amenities in Residential Township Development as published by the CSIR as well as the

minimum requirements of Hessequa Municipality.

1.1 MASS EARTHWORKS

Very little earthworks will be required to ensure a 2% free draining slope in a South Eastern direction.

Localised depressions will be filled with G7 material from commercial sources and compacted to 93%

MAASTO.



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1.2 ACCESS ROAD

Deca Consulting Engineers was contracted by Asla Devco to carry out a Traffic Impact Assessment on

the proposed single access to the complete development off the DR1528.

The following recommendations were made to ensure that the access comply with safe operating

standards:

An exclusive right turn lane is warrant on the eastern DR1528 approach.

It is suggested that taxi embayment’s be provided at the two community centres in the new

suburb.

A sidewalk be provided along the central north-west/south-east roads through the new

development.

1.3 INTERNAL ROADS

The Minimum Design and Construction Standards for Internal A Grade Engineering Services, as

approved by the Chief Director: Human Settlements, will be applicable for this project. The access road

will consist of a 6,0m wide road within the proposed 13m road reserve (Class 4). Road finishing will

consist of double and single surface treatments with stormwater pipework and inlet- and outlet structures.

The basis of the road and pavement design for the proposed development is set out in the table below:

Table 1 Road Design Criteria

Parameter Local Distributor Residential Access

Loop Residential Access

way (Class 4) (Class 5b) (Class 5d)

Category UB UC UC

Traffic Class E1 E0 E0

Structural Design Traffic 0.05 - 3 x 106 < 0.2 x 106 < 0.2 x 106

Surface Treatment Double surface treatment with 13,2 & 6,7mm aggregate and

single slurry seal

Single surface treatment with 13mm aggregate and two

slurry seals

Single surface treatment with 13mm aggregate and two

slurry seals



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Base and Sub-base from commercial sources

150mm G2 (98% MAASHTO) on 150mm G4 (95% MAASHTO) on 150mm Roadbed prep insitu Material (93% MAASHTO)

100mm G4 (98% MAASHTO) on 125mm G6 (95% MAASHTO) on 150mm Roadbed prep insitu Material (93% MAASHTO)

100mm G4 (98% MAASHTO) on

125mm G6 (95% MAASHTO) on

150mm Roadbed prep insitu Material (93%

MAASHTO)

Sub-grade (Historical geotechnical investigation, close to the site, suggest that the site is essentially underlain from ground surface by Aeolian silty sands which overlie calcarenites, calcareous sands, sands and gravelly soils of the Bredasdorp Group.

- - -

Carriage Way Width 6.0 4.5 4.5

Design Speed 50 km/h 40 km/h 30 km/h

Maximum Gradient 10% over 100m max 16% over 50m max 16% over 30m max

Minimum Gradient 0.5% 0.5% 0.5%

Cross Fall 2% 2% 2%

Bellmouths 8m Radius 8m Radius 8m Radius

1.4 STORMWATER

1.4.1 Major Systems

Two water courses cross the proposed development site. Free drainage of all roads will be in a South

Eastern direction. The lowest drainage point is located in the south eastern corner of the site.

Stormwater will drain, from this point, in a southerly direction to the Olive Grove storage dam.

Stormwater will be released via a Gabion energy dissipating structure, which will disperse stormwater at

a controlled rate thus reducing the risk of erosion. The structure will further trap waste transported from

storm water inlet structures.

1.4.2 Minor Systems and Storm water Design

Stormwater infrastructure will be constructed in accordance with the standard requirements and

specifications as agreed with the Hessequa Municipality.



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Stormwater runoff from the erven will gravitate towards the internal road network. Surface runoff will be

collected via kerb inlet structures and transported via pipe culverts to the lowest point on the site.

Servitudes will be provided for storm water reticulation as required.

Design criteria adopted for the development with regard to stormwater infrastructure is summarised as

follows:

Runoff rates will be determined according to the Rational Method.

Flood recurrence interval : 2 years

Pipe material : Concrete

Pipe class : 75D / 100D

Pipe diameters : min 375mm Ø up to diameter as required

Bedding : Class C

Inlets : Kerb and drop inlets as required

Manholes : Point of deflections on pipes

1.5 WATER

1.5.1 WATER SOURCE AND WTW

Melkhoutfontein is supplied with water from the Melkhoutfontein spring situated in the most Northern

corner of erf 570. A Report on Geohydrological Investigation for the Planned Expansion of the

Melkhoutfontein Village Area was completed by Groundwater Complete in May 2015.

The measured spring discharge records indicate that the minimum spring flow during the monitoring

period was around 9 l/s in January 2015 while the maximum rate was 21 l/s measured in July 2014.

The total discharge of the spring (after the off-take to the farmers of 95 000 m3 per year) over the year of

monitoring was in the order of 440 000 m3, which gives an average discharge of 13.9 l/s for the period.

Important to note from a bulk water supply perspective is that the highest demand period in the year is

through the warm summer and December holiday period when rainfall is at its lowest and the spring

discharge is also the lowest. At current spring flow, especially through December, is unable to supply in

the demand and water is used from storage.

Additional demand will definitely cause water shortages during this period. Although the exact spring

flow for a specific rainfall depth cannot be predicted, with only a year’s data, it is safe to surmise that a



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very dry season (<300 mm of rain) will lead to water shortages for the community at its current water

consumption.

When comparing current supply and demand figures it was very clear that the spring can easily supply

the demand during the cool and rainy winter months, but that demand far outstrips supply during the drier

and hot summer holiday season. The shortage during this period to especially Still Bay East is supplied

from the Olive Grove Dam storage. The dam is also fed by the other spring to the south of

Melkhoutfontein.

The solution for water supply to additional houses at Melkhoutfontein will thus be to develop a sufficient

buffer volume to keep up supply through the dry season or by securing other sources of bulk water supply.

Alternative bulk water sources

Groundwater from boreholes in the area was identified as a viable, cost-effective source as supply

boreholes have been developed in the past for community projects. We know that the aquifers in the

area are reliable since Still Bay West was supplied, prior to the building of the Olive Grove Dam, entirely

by groundwater from boreholes.

A number of boreholes occur in the Melkhoutfontein area that has been tested in the past to determine

the sustainable yield. Two of the boreholes were re-tested to affirm the overall condition of the boreholes

and confirm previous yields. Average sustainable yields were calculated at approximately 10 l/s for

borehole BH01B, while a yield of ± 12 l/s was calculated for borehole BH04. For the proposed housing

development at Melkhoutfontein it is strongly recommended that one or 2 of these boreholes be

commissioned for bulk water supply to augment the supply from the Melkhoutfontein Spring.



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1.5.2 WATER DEMAND

For this preliminary capacity analysis of the Melkhoutfontein water system, the total annual average daily

demand (AADD) and fire flows for the proposed development was calculated as follows:

• 585 Low Cost Housing units @ 500 ℓ/d/unit = 292,5 kℓ/d

Total 292,5 kℓ/d

• Fire flow criteria (Low risk) = 15 ℓ/s @ 7 m

1.5.3 EXISTING STORAGE CAPACITY

The criteria for the total reservoir volume used in the Melkhoutfontein Water Master Plan are 48 hours of

the AADD (of the reservoir supply zone).

The proposed development site will be connected via a link water main to the existing 160mm pipework

from the recently completed 0,5 Mℓ high level (TWL at 95m) reservoir. The reservoir was completed in

March 2018.

The proposed development consists over 42-hour storage capacity which is six hours less that the ideal

threshold. The shortfall has to be managed by Hessequa Municipality.



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1.5.4 BULK WATER DISTRIBUTION

The proposed development will be linked with a 1,160m long 160mm gravitation main directly connected

to the new gravitation pipe from the 0,5 Mℓ reservoir. The development will have no influence on the

existing water distribution network and therefore no upgrading of the existing network is envisaged.

1.5.5 INTERNAL WATER RETICULATION

New 160/110/75mm Class 12 uPVC water mains complete with isolating valves, fire hydrants and erf

connections will be provided. Erf connections will be made with HDPE PE80 PN12,5 pipes and terminate

at an Elster Kent water meter. Typical details are shown on drawing HESRIV-489/W01.

The basis of the water reticulation design for the proposed development is summarised in the table

below:

Table 2 Water Reticulation Design Criteria

PARAMETER GUIDELINE

Pipe materials for erf connections HDPE PE80 PN12,5

Pipe materials for reticulation mains uPVC (Class 12)

Minimum diameter for reticulation mains 75mm

Minimum diameter for erf connections serving two erven 25mm branching to 2 x 20mm

Minimum diameter for erf connections serving one erf 20mm

Valves AVK or VAC Best Valves (open clockwise)

Fire Hydrants AVK or VAC Best London V

1.6 SEWAGE TREATMENT AND SEWER MAINS

1.6.1 WWTW

The Development Bank of Southern Africa Status Quo Report confirms a WWTW design capacity of

0,150 Mℓ/d. To ensure that the existing WWTW will be able to handle the existing as well as the flow

from the proposed development the works will have to be upgraded to a design capacity of 0,45 Mℓ/d.

Melkhoutfontein has a waterborne sewer system which gravitates to a sewage pump station. Sewage is

pumped to an existing oxidation pond system. IX Consulting Engineers was contracted to investigate



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and come up with proposals for the most suitable alternative to treat and discard of wastewater at the

Melkhoutfontein WWTW. (Report under Annexure C)

The following three alternatives for the discarding of the Final Effluent were identified:

Irrigation of Final Effluent

Aquifer Recharge

Discharge of Final Effluent to the Goukou River

Hessequa Municipality confirmed the following daily flows to the WWTW (19/2/2019):

Average Daily Flow (ADF) (Pump station) : 185 Kℓ/d

Honey Sucker : 30 Kℓ/d

Current Daily Flow : 215 Kℓ/d

The following design criteria (assumptions) were used to determine the design capacity of the

existing/future works:

Sewage Flow from 585 new erven : 204,75 Kℓ/d

Total ADF (Existing plus flow plus full development) : 419,75 Kℓ/d

Sewage Flow at 100 ℓ/p/d.

BOD load = 0,055 kg/p/d.

60% Organic load reduction achieved in anaerobic ponds.

Organic loading rate on the primary pond 135 kg BOD/ha.d.

Design hydraulic retention time in secondary pond = 10 days.

Design hydraulic retention time in tertiary ponds = 15 days.



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The following external/bulk services and upgrading/extensions to the existing WWTW are required to

cater in the needs for Melkhoutfontein:

Pump station, Rising Main, WWTW & Irrigation:

New internal pump station for the development. (Pumping capacity of 8,0-10 ℓ/s)

1,240m Long x 110mm Ø rising main.

Upgrade existing Melkhoutfontein PS to 20 ℓ/s.

The following upgrading are recommended at the WWTW:

The existing primary and secondary pond to act together thus increasing

the primary capacity to required capacity.

To ensure sufficient secondary pond capacity it is proposed that the

dividing walls between the three tertiary ponds be demolished, the pond

enlarged to the northern boundary and the dam depth increased to 1,5m.

The existing polishing pond to act as a tertiary pond. An additional tertiary

pond to be constructed downstream of the existing tertiary pond in order

to provided additional tertiary capacity.

It is proposed that final polishing be done via a reed bed. (1 day retention)

It is anticipated that the reed bed polishing step will improve the quality of

final effluent by approximately 25%.

Provision be made for sludge drying facilities for the waste sludge

periodically withdrawn from the anaerobic ponds.

Effluent disinfection utilizing a PV panel to provide the required electrical

power.

The following irrigation infrastructure is proposed:

Holding dam for irrigation water.

Irrigation pump station, power supply and supply pipeline to small

holdings.

Permanent irrigation infrastructure on 28 ha small holdings.



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1.6.2 SEWER MAINS

The proposed development gravitates to the South Eastern corner of the development. It is proposed

that a new sewage pump station (8,0-10 ℓ/s) be constructed in the South Eastern corner of the

development and that sewage be pumped to the existing Melkhoutfontein PS drainage area. For this

preliminary capacity analysis of the Melkhoutfontein sewer system, the peak day dry weather flow

(PDDWF) for the proposed developments are calculated as follows:

• 585 Low Cost Housing units @ 500 ℓ/d/unit = 292,5 kℓ/d

70% of 292.5 kℓ/d = 204,75 kℓ/d

The proposed new development will have no capacity effect on the existing sewer reticulation system.

The existing Melkhoutfontein PS must be upgraded to a pumping capacity of 20 ℓ/s to accommodate the

existing and proposed development.

1.6.3 SEWER RETICULATION

A waterborne sewer reticulation system comprising of 160mm class 34 PVC sewer mains with solid shaft

fibre cement manholes complete with ductile iron double lipped manhole covers is proposed.

Each new erf will be provided with a 110mm Ø Class 34 uPVC connection with rodding eye and end cap

terminating one meter from the erf boundary. Typical details are shown on drawing HESRIV-489/S01.

1.7 ELECTRICAL SLEEVES

The position of electrical sleeves (110/160mm Class 34 PVC) will be determined in consultation with the

Electrical Engineer.

COST ESTIMATE : MELKHOUTFONTEIN HOUSING

The preliminary estimated cost for the provision of bulk/link services for the proposed development of

585 Low Cost erven is set out in the table below, viz.



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Table 3 : Cost Estimate

Description Costs

Costs associated with the provision of Bulk/link services

Water:

Development of Bore Hole BH01B R 180,000.00

75mm Ø Class 9 pipeline between BH01B and existing Melkhoutfontein Spring Pump Station

R 970,000.00

Link water main : 1160m long 160mm Ø Class 12 uPVC R 995,000.00

Sub-Total - A R 2,145,000.00

Sewer:

Sewage Pump Station (Civil, Mechanical & Electrical) R 550,000.00

Rising Main : 1240m long 110mm Ø Class 9 uPVC R 845,000.00

Upgrading of Existing Sewage Pump Station (20 ℓ/s) R 280,000.00

Sub-Total - B R 1,675,000.00

WWTW:

Extension of Oxidation ponds R 890,000.00

Provision of bypass from Pond 3 to 7 R 25,000.00

Pipe work and site works (including dealing with water) R 100,000.00

Polishing via reed bed system (2,279m²) R 400,000.00

Disinfection facility R 70,000.00

Sludge drying beds (480m²) R 864,000.00

Mobile sludge pump, including pipe work R 450,000.00

Sub-Total - C R 2,799,000.00

Irrigation:

New irrigation pump installation, gravity main, holding tank and power supply to irrigation system.

R 550,000.00

Supply and installation of irrigation system on 28 ha. R 1,120,000.00

Sub-Total - D R 1,670,000.00

External Road widening of DR1528:

Widening of DR1528 R 320,000.00

Sub-Total - E R 320,000.00

Sub-Total (A to E) Carried over R 8,609,000.00



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Sub-Total (A to E) Brought forward R 8,609,000.00

Plus : Preliminary & General @ 20% R 1,722,000.00

Plus : 5% Contingencies R 518,000.00

Plus : Engineering Fees @ 11% (Fees and Recoverable Costs) R 1,194,000.00

Plus : Water Use Licence Application and Geohydrological Study and Modelling R 3,000,000.00

Plus : Recoverable Cost (Survey, Soil Tests, Occupational Health & Safety and Administrative Costs – Excluding any Environmental Reports, Authorisation applications or Management Plans.

R 280,000.00

Total (Excluding 15% VAT) R15,323,000.00

CONCLUSION

We trust that the information provided in this report will provide an understanding with regard to the

required link/bulk infrastructure for the development of 585 low cost housing erven on Portion 111 of the

Farm Melkhoutfontein 480.

GIDEON PEPLER Pr Tech Eng HESSEQUA CONSULTING ENGINEERS

12 August 2019



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ANNEXURE A : DRAWINGS

HESRIV-489-BW-01 : BULK WATER LAYOUT

HESRIV-489-BS-01 : BULK SEWER LAYOUT

HESRIV-489-W01 : WATER RETICULATION TYPICAL DETAILS

HESRIV-489-S01 : SEWER RETICULATION TYPICAL DETAILS



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ANNEXURE B : TRAFFIC IMPACT ASSESSMENT

1

MELKHOUTFONTEIN LOW COST HOUSING PROJECT TRANSPORT IMPACT ASSESSMENT

JUNE 2019

Deca Consulting Engineers PO Box 359 Villiersdorp 6848 Tel: 028 840 2366

Hessequa Municipality PO Box 29 Riversdal 6670 Tel: 028 713 8000

MELKHOUTFONTEIN LOW COST HOUSING PROJECT TRANSPORT IMPACT ASSESSMENT

1

1. BACKGROUND

Deca Consulting Engineers were appointed by Asla Devco (Pty) Ltd to assess the transport impact of the proposed subsidised housing development on Portion 111 of the Farm Melkhoutfontein No. 480,. The transport impact assessment is submitted as part of the land use planning application. The report is based on the Draft Layout Plan by Urban Dynamics dated 12 February 2019, a copy of which is attached.

Melkhoutfontein is located to the west of the existing town of Melkhoutfontein and to the

north of Melkhoutfontein Primary School, approximately 5 kilometres north of Stilbaai in the Hessequa Municipal area. The town is accessed from the N2 via Main Road (MR) 332 (R305) and Divisional Road (DR) 1528. Minor Road (OP) 4896 serves as the main east-west road through Melkhoutfontein. The location of the development as well as the high order roads in the vicinity are shown in Figure 1.

The settlement was originally established as a fisherman’s village and today serves mainly

as a dormitory town to Stilbaai. There is a school, a clinic, churches, sports fields and small spaza-type shops, but no real commercial or industrial opportunities. Most Melkhoutfontein residents travel to Stilbaai or Riversdale for administrative, shopping and work purposes.

2. DEVELOPMENT PROPOSAL

The attached Site Layout Plan shows that the property will be developed in two phases. The first phase will consist of 253 residential erven, one business erf and one erf each zoned for utility and community use. The second phase will have 332 residential erven, one erf zoned for community use and 4 erven zoned for utilities. Both phases will obtain access via a single point off DR1528.

3. EXISTING ROADS AND TRAFFIC

Important roads that will be impacted by the development include the MR332 (R305; Class 3 Minor Arterial), DR1528 (Class 4 Collector Roads) and OP4896 (Class 5). The RCAM Classification was obtained from the Western Cape Road Network Information website.

Traffic counts were done at the MR332 / DR1528 intersection on Tuesday 11 June 2019.

This intersection is a T-junction with stop control on DR1528. Peak hours were observed between 6:45 and 7:45 in the morning and between 16:30 and 17:30 in the afternoon. The counts show that 10% of the vehicles counted during 12-hour count were minibus taxis and 2% was buses.

The intersection was analysed using SIDRA software. The analysis indicates that all

movements operate at a level of service A during both the morning and afternoon peak hours. The good service levels were confirmed during a site visit. Existing 2019 traffic volumes and service levels are shown in Figure 2.

4. BACKGROUND TRAFFIC

It is expected that both phases will be completed and most homes occupied by the end of 2022. Existing 2019 traffic volumes were increased by 4,4% per annum as per the historical growth rate obtained from the Western Cape Provincial Road Network Information System to calculate Year 2022 baseline traffic volumes. The analysis of the MR332 / DR1528 intersection with the baseline volumes shows that all movements will continue to operate at a level of service A during the morning and afternoon peak hours. See Figure 3.

2

5. DEVELOPMENT TRIPS For the purpose of this report it was assumed that one of the community erven would be

used for a church and the other for a crèche. Trip generation rates for the church and crèche were obtained from the 2013 COTO TMH7 South African Trip Data Manual. It was assumed that only 50% of the crèche trips would be private transport trips, with the remainder being non-motorised or public transport trips. The trip generation rate for the subsidy housing component was obtained from the older South African Trip Generation Rates document, as the newer manual does not give a rate for low income households. Although the rate for the subsidised housing component already takes into account the high public and non-motorised modal share, the 2019 traffic counts for Melkhoutfontein indicate that the private transport trip generation rate for this town is closer to 0,4 trips per residential unit. Based on these rates, it was calculated that the development will have the potential to generate 253 private vehicle trips (65 in, 188 out) during the morning peak hour and 259 trips (175 in, 83 out) during the afternoon peak hour. The trip generation details are shown in Tables 1 and 2.

It was assumed that the majority of trips to and from the creche and church would be from

Melkhoutfontein Village, whereas the most residential trips would be to and from MR332, where it was split 70:30 to the south (Stilbaai) and north (N2), respectively. The trip distribution is shown in Figure 5.

Table 1: Morning peak hour trip generation potential

Layout Trip rate % In % Out

Total trips

Trips in

Trips out

Phase 1 Residential 253 units 0,42 per unit 0,25 0,75 107 27 80

Church 100 seats 0,05 per seat 0,55 0,45 5 3 2


Crèche 80 kids 0,5 per child 0,5 0,5 40 20 20

Total 253 65 188 Table 2: Afternoon peak hour trip generation potential

Layout Trip rate % In % Out

Total trips

Trips in

Trips out


Church 100 seats 0,05 per seat 0,5 0,5 5 3 3


Crèche 80 kids 0,5 per child 0,5 0,5 40 20 20

Total 259 175 83 5. TRAFFIC IMPACT Development trips were added to Year 2022 background traffic volumes. The MR332 /

DR1528 intersection as well as the DR1528 / Development access intersection were analysed with the resultant total traffic volumes. The analysis shows that all movements at both intersections will operate at a level of service A during the morning and afternoon peak hours. It can be concluded that, although the development will generate a considerable number of trips, the traffic impact thereof will be low.

3

Melkhoutfontein

School

Although no improvements will be required at the DR1528 / Development access intersection, an exclusive right turn lane is warranted on the eastern DR1528 approach for safety purposes, based on the Western Cape Provincial Road Access Guidelines warrants.

6. PUBLIC TRANSPORT As stated in paragraph 3, approximately 10% of the vehicles counted on DR1528 were

minibus taxis. Another 2% of the vehicles were buses, presumably school buses. If it is assumed that taxis carry an average of 14 persons, buses carry 60 persons and cars two persons, it means that 29% of people in Melkhoutfontein using motorised transport use taxis, 32% use buses and 39% use cars.

Formal taxi embayments were provided on either side of MR322 just south of the DR1528

intersection during the 2017 reconstruction of MR322. Counts were done at the taxi stops on 11 June 2019. The counts show that only one minibus taxi stopped on the western side of the road during the 12-hour counting period, while ten taxis stopped on the eastern (Melkhoutfontein) side. During the same period, 52 taxis travelled from Melkhoutfontein towards Struisbaai with 55 taxis doing the reverse trip.

It is expected that the new Melkhoutfontein development will generate a considerable

number of public transport trips. Due to the size of the development it is expected that minibus taxis will establish regular routes through the area to pick up and drop off passengers. It is suggested that taxi embayments should be provided at the two community centres in the new suburb.

7. NON-MOTORISED TRANSPORT There is a paved footpath linking Melkhoutfontein to the primary school and MR332. The

new development will be provided directly to the north of the footpath, which means that the new development will also be served by the footpath (See Diagram 1 below). The Site Development Plan shows that provision has been made for pedestrian links to the footpath. There is also a paved sidewalk along the eastern side of MR332 all the way from the Melkhoutfontein footpath to the town of Stilbaai. On the day of the traffic counts, only twelve pedestrians were recorded making use of the footpath from the MR332 side.

Diagram 1: Footpath between MR332 and Melkhoutfontein

4

The existing non-motorised transport infrastructure will be sufficient to accommodate the new development. The only new infrastructure recommended, is a sidewalk along the central north-west / south-east road through the new development.

8. CONCLUSIONS It can be concluded from the study that the proposed low-cost housing development in

Melkhoutfontein will have a low traffic impact. Other important findings are summarised as follows:

The development will consist of residential erven, one business erf and one erf each

zoned for utility and community use. The second phase will have 332 residential erven, one erf zoned for community use and 4 erven zoned for utilities;

The full development will have the potential to generate 253 private vehicle trips (65 in, 188 out) during the morning peak hour and 259 trips (175 in, 83 out) during the afternoon peak hour;

Public transport vehicles account for 12% of the vehicles counted on DR15258, the access road to Melkhoutfontein;

All roads and intersections that will be affected by the proposed development currently operate at excellent service levels and will continue to do so with the addition of development trips;

There are taxi embayments next to MR332 within walking distance from the proposed development;

The development will be located directly north of a paved footpath linking Melkhoutfontein to the primary school and MR332. The Site Development Plan shows that provision has been made for pedestrian links to the footpath.

9. RECOMMENDATIONS It is recommended that the proposed Melkhoutfontein low cost housing development be

approved, on condition that the following recommendations are considered:

An exclusive right turn lane is warranted on the eastern DR1528 approach, based on the Western Cape Provincial Road Access Guidelines warrants;

It is suggested that taxi embayments should be provided at the two community centres in the new suburb;

A sidewalk should be provided along the central north-west / south-east road through the new development.

We trust that you will find this report in order. Kindly contact Liezl du Plooy at telephone number 082 338 6466 should you have any questions. Yours truly Liezl du Plooy M. Eng Pr. Eng Deca

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CLIENT

INDEMNITY

URBAN DYNAMICS MAKES NO WARRANTY OF ANY KIND, EXPRESSED OR IMPLIED, WITH REGARD

TO THE DATA AND SHALL NOT BE HELD LIABLE IN ANY EVENT FOR ANY INCIDENTAL OR

CONSEQUENTIAL DAMAGES IN CONNECTION WITH OR ARISING OUT OF THE USE OF THIS DATA.

THE DATA REMAINS THE SOLE PROPERTY OF THE CLIENT AND MAY ONLY BE USED FOR THE

PURPOSES OF A PROJECT WITH THE PRIOR WRITTEN APPROVAL OF THE CLIENT.

12 Feb 2019

See Linescale

FILE NAME:

PLAN NO.

SCALE

DATE

RESERVED

COPYRIGHT

DRAFT LAYOUT PLAN

MELKHOUTFONTEIN

1

PLEASE NOTE:

All boundary line positions, distances and property sizes need to be verified

by a Professional Land Surveyor.

FAX: (021) 948 1588

TEL: (021) 948 1545

Website: www.udwc.co.za

URBAN DYNAMICS WESTERN CAPE INC REG. No : 95/09962/21

2nd Floor Tygervalley Chambers

Willie van Schoor Avenue

Bellville 7530

PO Box 2445

Bellville

7535

PORTION 111 OF THE FARMMELHOUTFONTEIN No. 480

DRAFT LAYOUT PLAN

FOR DISCUSSION PURPOSES ONLY

Application Area - ±17.87ha

Building Line Setback ±40m

Graves

Contours (0.5m intervals)

PHASE 1

PHASE 2

AutoCAD SHX Text

137/480

AutoCAD SHX Text

RE/63/480

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1503

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1504

PORTION 111 OF THE FARM MEKLHOUTFONTEIN NO. 480LOCALITY PLAN

PO Box 35982 FairwaysTheewaterskloof EstateVilliersdorp6848

Tel: 028 840 2366e-mail: [email protected]

FIGURE 12019-06-10

Proposeddevelopment

OP4896

MelkhoutfonteinPrimary

To N2

MR332 (R305)

DR1528

STILBAAI

MELKHOUTFONTEIN

OP4

895

To Gouritsmond

A/A A/A A/A A/A78 7 1 276 16 A/A 0 2 1 0

A/A 48 131 DR152813 8 A/A 0 0 A/A

75 41 130 54 A/A 142 61 A/A105 117A/A A/A

LEGEND

75 Morning peak hour volume105 Afternoon peak hour volumeA/A AM/PM Movement service levels

Bus D

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FIGURE 2 2019-06-21

MR3

32 Farm

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EXISTING (2019) TRAFFIC VOLUMES AND SERVICE LEVELS

A/A A/A A/A A/A86 8 1 284 18 A/A 0 2 1 0

A/A 53 145 DR152814 9 A/A 0 0 A/A

83 45 144 60 A/A 157 67 A/A116 129A/A A/A

LEGEND


FIGURE 3 2019-06-21

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YEAR 2022 BACKGROUND TRAFFIC AND SERVICE LEVELS

16 043 0

54 143 DR152846 21 0,3 31 53

38 107 48 0,7 153 0 55100 69 0 34

LEGEND

0 Morning peak hour volume0 Afternoon peak hour volume0 AM/PM Movement service levels

FIGURE 4 2019-06-21

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DISTRIBUTION OF TRIPS GENERATED BY FARM 480/111 MELKHOUTFONTEIN DEVELOPMENT

A/A A/A A/A A/A A/A86 24 A/A 0 2 1 0 284 61 A/A 53 145 1 0 0

A/A 54 143 DR152860 30 A/A 0 0 A/A

83 83 251 108 A/A 153 0 55 157 67 A/A116 229 69 0 34 31 53 A/AA/A A/A A/A A/A A/A

LEGEND


FIGURE 5 2019-06-21

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TOTAL 2022 TRAFFIC VOLUMES AND SERVICE LEVELS



P a g e | 18

ANNEXURE C : TECHNICAL REPORT FOR THE UPGRADING OF THE MELKHOUTFONTEIN

WASTEWATER TREATMENT WORKS

TECHNICAL REPORT FOR THE UPGRADING OF THE MELKHOUTFONTEIN WASTEWATER

TREATMENT WORKS

301459

[05 August 2019]

COMPILED FOR: COMPILED BY:

ASLA DEVCO PO BOX 118 Gordons Bay 7151 Contact person: David Douglas Telephone: +27(0)21 912 3000 e-mail: [email protected]

iX engineers (Pty) Ltd 31 Allen Drive Loevenstein Cape Town 7350 Contact person: Sonel van Wageningen Telephone: +27(0)21 912 3000 email: [email protected]

© Copyright 2012 iX engineers (Pty) Ltd

ASLA DEVCO UPGRADING OF THE MELKHOUTFONTEIN WASTEWATER TREATMENT WORKS

PROJECT 301459 – UPGRADING OF THE MELKHOUTFONTEIN WASTEWATER TREATMENT WORKS

REV DESCRIPTION ORIG REVIEW DATE CLIENT

APPROVAL DATE

A Issued for internal review

S van Wageningen

A Beeslaar

2019/08/05

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Disclaimer

This report has been prepared on behalf of and for the exclusive use of ASLA DEVCO, and is subject to

and issued in accordance with the agreement between ASLA DEVCO and iX engineers (Pty) Ltd. ASLA

DEVCO and iX engineers (Pty) Ltd accepts no liability or responsibility whatsoever for it in respect of any

use of or reliance upon this report by any third party.

Copying this report without the permission of ASLA DEVCO and iX engineers (Pty) Ltd is not permitted.


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EXECUTIVE SUMMARY

ASLA Devco appointed iX engineers for the investigation and compilation of a technical report to qualify the

extent of the upgrading required at the Melkhoutfontein Wastewater Treatment Works (WWTW), in order to

accommodate the sewage to be generated by a proposed new housing development.

The current oxidation pond system has an estimated capacity of 0.15Ml/d. A new low-cost housing

development is planned for 585 erven. The additional flow from these developments will exceed the capacity

of the existing Wastewater Treatment Works and would require upgrading of the works to ensure a treatment

capacity of + 0.45Ml/d.

The proposed upgrade of the WWTW would require an extension of the pond systems in terms of the secondary pond volume (retention) and the tertiary pond volume (retention) as well as final polishing before discharge/re-use. In addition to this, the following infrastructure and treatment processes are recommended for inclusion with the WWTW upgrade:

• Effluent disinfection utilizing a PV panel to provide the required electrical power.

• Provision of sludge drying facilities for the waste sludge periodically withdrawn from the anaerobic ponds

The estimated project cost for the extension to the existing ponds is detailed below:

Estimated Project Cost

Description Cost

Preliminary and General Cost (20 %) R 589,800.00

Extension of oxidation ponds (+ 3000m3 @R80/m3) + lining of + 5000m2 @R130/m2) R 890,000.00

Provision of a bypass from Pond 3 to Pond 7 R 25,000.00


Polishing via a reed bed system (2 279m2) R 400,000.00


Sludge drying beds (480 m2 @R1 800/m2) R 864,000.00

New gravity line, holding tank and pump for irrigation R 150,000.00

Mobile sludge pump (incl pipe work) R 500,000.00

SUBTOTAL R 3,588,800.00

Contingencies (5%) R 179,440.00

Professional fees and disbursements (10%) R 358,880.00

TOTAL R 4,127,120.00

The extension of the pond system as recommended above should be sufficient to provide a final effluent that could be irrigated on a nearby field, however, this can only be confirmed upon completion of the following studies:

• Water Use License Application (18-24 maande)

• Waste Licence Application

• Geohydrological Study including hydrocensus

• Geohydrological Modelling


It is then anticipated that the cost associated with the aforementioned studies would be in the order of R3,000,000.00 (excl. VAT). It is understood that the Stellenbosch University may be in the process of conducting studies to investigate Aquifer Recharge within the catchment area of the Hessequa Municipality with funding being provided by the Norwegian Government. This initiative should be explored further and gauged whether the aforementioned investigation could be included within the study.


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CONTENTS

EXECUTIVE SUMMARY ................................................................................................................................. II

1. BACKGROUND ................................................................................................................................ 1

2. DESCRIPTION OF THE EXISTING MELKHOUTFONTEIN WWTW .............................................. 1

2.1 CAPACITY AND FLOW VOLUMES ................................................................................................. 1

2.2 EFFLUENT QUALITY ....................................................................................................................... 3

3. NEED FOR UPGRADING OF THE EXISTING WWTW ................................................................... 4

4. DESIGN CAPACITY REQUIRED ..................................................................................................... 5

5. UPGRADING OF THE MELKHOUTSFONTEIN WWTW ................................................................ 5

6. EFFLUENT DISCHARGE OPTIONS ............................................................................................... 7

6.1 OPTION 1: IRRIGATION OF FINAL EFFLUENT ............................................................................. 7

6.2 OPTION 2: AQUIFER RECHARGE .................................................................................................. 8

6.3 OPTION 3: DISCHARGE TO THE GOUKOU RIVER ...................................................................... 9

7. COST ESTIMATE ........................................................................................................................... 10

8. CONCLUSION ................................................................................................................................ 10

APPENDICES

APPENDIX 1 - LABORATORY RESULTS

APPENDIX 2 - LAYOUT OF PROPOSED EXTENSIONS

APPENDIX 3 – AREA PROPOSED FOR FINAL EFFLUENT IRRIGATION

APPENDIX 4 – AQUIFER MAP

APPENDIX 5 – STILBAAI MARINE PROTECTED AREA

LIST OF TABLES

Table 1: Effluent Quality Results ..................................................................................................................... 3

Table 2: Flow estimation based on the planned development ........................................................................ 4

Table 3: Current and Future Treatment Capacity Required ............................................................................ 5

Table 4: Estimated Construction Cost ...........................................................................................................10


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LIST OF FIGURES

Figure 1: Current layout of the existing Melkhoutfontein WwTW .................................................................... 2

Figure 2: Area available on site and layout of proposed new extensions ....................................................... 6


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1. BACKGROUND

ASLA Devco appointed iX engineers for the investigation and compilation of a technical report to determine

the extent of the upgrade requirements at the Melkhoutfontein Wastewater Treatment Works (WWTW), in

order to accommodate the additional sewage generated by the proposed new housing development.

Melkhoutfontein falls within the demarcated boundaries of the Hessequa Municipality in the Western Cape

and is situated 335km East of Cape Town and 35km South East of Riversdale.

During conversations with the Hessequa Municipality, it was made clear that the WWTW should also address

the following concerns.

• Effluent disinfection

• Effluent polishing and disposal

• De-sludging of anaerobic ponds, as well as providing drying facilities for the waste sludge

The ensuing report provides context regarding the existing wastewater treatment works as well as the need

and proposed means by which the existing works should be upgraded.

2. DESCRIPTION OF THE EXISTING MELKHOUTFONTEIN WWTW

2.1 CAPACITY AND FLOW VOLUMES

The WWTW has an estimated capacity of 0.15Ml/d (according to the Development Bank of Southern Africa

Status Quo Report) and consist of the following processes:

1. Inlet works with manual screen and grit channels

2. Two anaerobic ponds, 3.5m deep with an approximate volume of 588m³ and 456m³ respectively

3. One primary pond with a surface area of + 8558m²

4. A Secondary pond with a volume of + 1050m3 (depth 0.7m)

5. Three tertiary ponds with a combined volume of + 3155m3 (depth 1.1m)

6. A polishing pond with a volume of + 3987m3 (Depth 1.5m)

An aerial photo of the Melkhoutsfontein WwTW can be seen in Figure 1 below.



Figure 1: Current layout of the existing Melkhoutfontein WwTW (Oxidation Pond System)



2.2 EFFLUENT QUALITY

Effluent quality results received (refer Appendix 1) for June 2019 indicate that the ponds currently provide

sufficient treatment of the sewage flow received. The Conductivity seems to be elevated, however this can

be attributed to the high salinity content of the boreholes supplying the town with potable water. The effluent

quality results are summarized below in Table 1 (also refer Appendix 1). There is however no information

available regarding industries that may discharge to the WWTW.

Table 1: Effluent Quality Results

Based on the Government Notice no. 36820, of 6 September 2013, the effluent quality harvested from a treatment works up to a capacity of 500m3/d that is not discharged in a water course should comply with the following limits:

• pH – not less than 6 or more than 9 pH units;

• Electrical conductivity – not exceed 200 mS/m;

• Chemical Oxygen Demand (COD) – does not exceed 400mg/l, after removal of algae;

• Feacal coliforms – do not exceed 100 000 per 100ml. A comparison with the effluent results in the table above, show consistent compliance with the Limits as listed. Since an oxidation pond process is natural, and subject to influences which are random – weather, and predominant microbiological species, etc – a pond system cannot consistently produce effluent of a precise standard. The introduction of a reed bed polishing step will however improve the quality by approximately 25% while addressing the issue of Contaminants of Emerging Concern. Pond performance is influenced by variations of seasons and climate, for example ammonia removal is usually good in summer but poor in winter. Algal blooms are typically a summertime occurrence, an impact on COD, SS and bacteria levels. Therefore, compliance with General Limit Values (GLV), according to the Government Notice no. 36820, of 6 September 2013, cannot be guaranteed.

AnalysesResults

25/6/19

Results

28/5/19

Results

24/4/19

Results

25/3/19

Results

25/2/19

Results

28/1/19

Results

18/12/18

Results

26/11/18

Results

29/10/18

Results

25/9/18

Results

27/8/18

Results

23/7/18Average

pH (at 25°C) 8.38 8.7 9.48 9.5 10 9.39 8.58 9.53 8.2 8.12 8.3 8.19 9

Conductivity (mS/m) (at 25°C ) 240 305 295 315 325 330 320 290 275 255 265 305 293

Total Suspended Solids (mg/l) 34 38 80 42 117 83 58 1 43 105 81 10 58

Ammonia Nitrogen (mg/l as N) 19 9.4 2.5 1.9 <0.10 2.6 1.3 180 5.4 37.7 59.2 58.8 34

Nitrate & Nitrite Nitrogen (mg/l as N) 1.5 0.38 0.55 <0.20 <0.20 0.36 <0.20 1.6 11.7 8.3 0.76 <0.20 3

Nitrate Nitrogen (mg/l as N) 1.2 <0.20 <0.20 <0.20 <0.20 <0.20 <0.20 <0.20 0.8 0.8 0.27 <0.20 1

Nitrite Nitrogen (mg/l as N) 0.35 0.22 0.46 0.25 <0.20 <0.20 <0.20 0.35 10.9 7.5 0.49 <0.20 3

Ortho Phosphate (mg/l as P) 4.7 3.5 1.7 0.89 0.17 0.98 4 58 4.5 6.8 5 7.1 8

Chemical Oxygen Demand (mg/l) 108 113 179 166 264 275 188 1.1 172 182 130 95.3 156

Free Chlorine (mg/l) <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05 <0.05

E.coli (count per 100ml) 13 11 4 10 <1 16 84 1 7 77 112 3 31

Faecal Coliforms (count per 100ml) 13 11 4 10 <1 16 84 0.55 7 77 112 3 31



3. NEED FOR UPGRADING OF THE EXISTING WWTW

According to a report entitled Draft Services Report for Civil Engineering Services on Portion 111 of the Farm

Melkhoutfontein No 480 for Hessequa Municipality, February 2019, a new low-cost housing development is

planned for 585 erven. The additional flow from these developments will exceed the capacity of the existing

WWTW.

Given the development that is planned, a few assumptions were made based on values found in literature

in order to obtain figures that can be used to base a design on. Table 1 show the assumptions made.

Table 2: Flow estimation based on the planned development

Planned Residential Development

Type of Dwelling Low Income

Number of units planned 585

People per dwelling 3.5

Effluent per person per day (l) 100

Total effluent per day (kl/d) 204.8

Total existing sewage flow (kl/d) 215

Total future flow (existing + new) (kl/d) 419.75

With the additional flow, the capacity of the works should increase from 0.15Ml/d to 0.42Ml/d.

The above flow figures were also confirmed using the census figures for 2016. During this assessment a

population of 2610 people was indicated. If an estimated additional population of 2047 people (585 new

erven X 3.5 persons/erf) is added, a future population of + 4647 people is calculated. At a sewage flow of

100l/p/d a total estimated future sewage flow of 465 kl/d is envisaged, which correlates with the above

figures.

Furthermore, in terms of the organic- and hydraulic loading, the following assumptions were made:

• BOD load – 0.055 kg/p/d

• 60% organic load reduction achieved in anaerobic ponds. Two separate ponds are preferred in order to

provide flexibility should maintenance be required

• Organic loading rate on the primary pond – 135 kgBOD/ha.d

• Design hydraulic retention time in secondary pond – 10 days

• Design hydraulic retention time in tertiary ponds – 15 days (retention ideally to be provided in 3 separate

ponds (5 days each), or in at least two (2) separate ponds)



4. DESIGN CAPACITY REQUIRED

Table 3: Current and Future Treatment Capacity Required

Unit Current Estimated Capacity Future Requirement

(420 Kl/d)

Anaerobic Ponds 1 044m3 (Two ponds: 456m3 and 588m3) 577m3 per pond

Primary Pond 8 558.4m2 10 260m2

Secondary pond 1 050m3 4 197m3

Tertiary Pond 3 155m3 6 000m3

Polishing 3 987m3 3 570m2

Note: The design criteria used to determine the capacity of the individual ponds is based on empirical values,

as indicated above. Thus, although the anaerobic ponds and primary pond seem to be slightly undersized

sufficient retention is provided downstream with the proposed upgrade that this should not negatively impact

the final effluent quality.

The estimated volumes listed above was calculated using the dam depths as provided in the report; Draft

Services Report for Civil Engineering Services on Portion 111 of the Farm Melkhoutsfontein No 480 for

Hessequa Municipality.

5. UPGRADING OF THE MELKHOUTSFONTEIN WWTW

Based on the treatment requirements identified in Section 4 of this report, the design capacity of the various

components comprising the oxidation pond system can be calculated. Several factors determine the choice

of treatment technology to be adopted when considering upgrading of any wastewater treatment works. For

now, the main factors are treatment efficiency with regards to operational input and cost. Considering the

remote location and existing infrastructure or lack thereof (availability of electricity) the most viable option at

this stage is to extend the oxidation pond system to ensure sufficient treatment before final effluent discharge.

The proposed upgrade of the WWTW would require an extension of the pond systems in terms of the

secondary pond volume (retention) and the tertiary pond volume (retention) as well as final polishing before

discharge/re-use.

It is recommended that pond three (3) act a primary pond together with pond two (2), thus an increased

surface area would be available. In order to ensure sufficient secondary pond volume it is proposed to

combine ponds four (4) to six (6) into one pond. With the demolition of the dividing walls between dams four

(4) and five (5) and five (5) and six (6) it is also recommended to deepen this pond to 1.5m and to line this

pond to reduce any possibility of ground water pollution due to infiltration.

Tertiary pond capacity will then be achieved in pond seven (7). An additional pond should be constructed

downstream of pond seven (7) in order to provided additional tertiary capacity.

Finally, it is proposed to provide final polishing via a reed bed, with retention of 1 day. It is anticipated that

the reed bed polishing step will improve the quality of final effluent by approximately 25%.



Below is the proposed layout including the extensions as recommended.

Figure 2: Area available on site and layout of proposed new extensions (refer Appendix 2 for an A3

version of this layout)

Apart from increasing the oxidation ponds during the upgrading of the works, there are several other aspects

of the existing works that also require attention and should be addressed during the upgrade. The following

infrastructure and treatment processes are also recommended.

• Effluent disinfection utilizing a PV panel to provide the required electrical power.

• Provision of sludge drying facilities for the waste sludge periodically withdrawn from the anaerobic ponds



6. EFFLUENT DISCHARGE OPTIONS

As part of the project brief, iX engineers were requested to investigate effluent disposal options. The existing

works do not have a formal effluent disposal mechanism in place and with the anticipated increase in flow

stemming from the proposed development a solution must be found which would address the disposal of

effluent in an environmentally responsible manner.

Several options were discussed with the Hessequa Municipality and various stakeholders and these options

include:

• Irrigation of final effluent on land allocated for such an activity

• Aquifer Recharge

• Discharge to the Goukou River

These options are discussed in further detail below.

6.1 OPTION 1: IRRIGATION OF FINAL EFFLUENT

This option would entail the irrigation of land adjacent to the existing WWTW site. At the time of the report,

an area suitable for such an activity have not been identified by relevant stakeholders. However, the land

adjacent to the WWTW appear to be suitable for such an activity, pending agreement and commitment from

the landowners. It is estimated that an area of approximately 28ha would be required for irrigation of luserne,

which could be used as feed for livestock.

The proposed area is identified in Appendix 3 and based on the information obtained from the Title Deeds

Office, the properties impacted are owned by the Hessequa Municipality. Engagement with the Municipality

would therefore be required. The area, however, may impact on the existing aquifer which is classified as a

Major Aquifer that is considered Most Vulnerable and has a Very High Susceptibility. Refer to Annexure 4

for aquifer location and details.

Should the proposed area not be aligned with current borehole location and abstraction the location for

irrigation may have to be revised. Refer to Appendix 3 for location of the existing boreholes in relation to the

area proposed for irrigation.

It is envisaged that this option would entail the following studies and investigations to confirm that the aquifer

is not negatively impacted by the irrigation activity:

• Water Use License Application (18-24 months)

• Geohydrological Study and Modelling

Based on feedback from GHT Consulting Scientists and Groundwater Africa as well as similar studies

conducted within the Atlantis area the cost associated with the geohydrological investigation is anticipated

to be in the order of R3,000,000.00 (excl. VAT). This would include the construction of specialist boreholes



to accommodate inflow as well as monitoring boreholes to determine aquifer properties. In addition, recharge

studies to determine max influx into the aquifer to prevent forming wetlands forms part of the study.

It is understood that the Stellenbosch University may be in the process of conducting studies to investigate

Aquifer Recharge within the catchment area of the Hessequa Municipality with funding being provided by

the Norwegian Government. This initiative should be explored further and gauged whether the

aforementioned investigation could be included within the study.

6.2 OPTION 2: AQUIFER RECHARGE

This option would entail the disposal of final effluent through Aquifer recharge.





The same activities associated with Option 1 will apply to Option 2, but since this option entails direct

recharge, the impact on the aquifer may be considered as an increased risk and may require more stringent

effluent quality requirements. If it is found that the water quality stemming from the WwTW for aquifer

recharge is not of an acceptable level the oxidation pond process configuration may have to be replaced by

an Activated Sludge Plant. The cost associated with such a plant is detailed below in Table 4.

Table 4: Project Cost for 0.45Ml/d Activated Sludge WWTW

Description Civil Cost Mechanical Cost

Inlet works R 600,000.00 R 200,000.00

Biological reactor R 1,330,000.00 R 650,000.00

Waste from aerobic basin R - R 100,000.00

Secondary settling tank – 16 m diameter R 500,000.00 R 300,000.00

Chlorine contact channel R 500,000.00 R 120,000.00

Chlorine installation to SANS 10298:2005 standards R 350,000.00 R 280,000.00

Mixed liquor recycle pumps (duty/standby) R - R 250,000.00

RAS pumps (duty/standby) R - R 260,000.00

Sludge drying beds R 800,000.00 R 50,000.00

Control building R 520,000.00 R -

Irrigation pumps (duty/standby) R - R 150,000.00

Automation, scada and security camaras R - R 600,000.00

Electrical installation R - R 750,000.00

Subtotal 1 R 4,600,000.00 R 3,710,000.00

Total Construction (Subtotal 2) R 8,310,000.00

25 % Preliminary and General R 2,077,500.00

10 % Contingencies R 1,038,750.00

Subtotal 3 R 11,426,250.00

Professional Fees R 1,142,625.00



Geotechnical investigation R 100,000.00

Disbursements R 300,000.00

Optional Supervision R 600,000.00

TOTAL (Excluding VAT) R 13,568,875.00

VAT R 2,035,331.25

TOTAL (Including VAT) R 15,604,206.25

6.3 OPTION 3: DISCHARGE TO THE GOUKOU RIVER

This option would entail the construction of a pump station and pipeline to discharge to the Goukou River.

The Goukou River in located within the Goukou Estuary. It must be noted that the Goukou Estuary forms

part of the Stilbaai Marine Protected Area (MPA), which includes the area between Noordkapperspunt

(34°23’.964 S, 21°24’.800 E) and Rietvleivywers (34°21’.676 S, 21°30’.976 E), out to approximately 4.2 km

offshore, and includes the estuary of the Goukou River to a point 15 km upstream of the shore. Refer to

Appendix 5 for details of the extent of the Stilbaai MPA.

As per the National Environmental Management: Integrated Coastal Management Act (No. 24 of 2008)

(ICMA) (as amended), the Department of Environmental Affairs (DEA) has the responsibility for regulating

land-derived effluent discharges into coastal waters. In terms of Section 69 of ICMA, no person is permitted

to discharge effluent originating from a source on land into coastal waters except in terms of a GDA or a

Coastal Waters Discharge Permit (CWDP). Discharge into the MPA would not be authorized, however should

the discharge point be located outside of the boundaries of the MPA, an estuarine discharge of this nature

will require the following studies and investigations:

• Water Use License Application (18-24 months)

• Environmental Basic Assessment Process (9-12 months)

• Freshwater Impact Assessment

• Possibly Botanical Impact Assessment Study

• Estuarine Impact Assessment

• Dispersion Modelling

• Coastal Waste Discharge Permit

It is anticipated that the cost associate with the studies will be in the order of R500,000.00 (excl. VAT). In

addition, the construction of approximately 10km of pipeline as well as a pump station would be required in

order to discharge upstream of the Stilbaai MPA and it is anticipated that the construction cost would be in

excess of R5,000,000.00. Based on the complexity of the studies, the lengthy approval process and

associated risk as well as the anticipated cost this option is not considered a viable option for effluent

discharge.



7. COST ESTIMATE

The cost of construction for the extension to the existing ponds, as well as providing the additional

infrastructure as discussed, is tabled below.

Table 5: Estimated Project Cost

Description Cost

Preliminary and General Cost (20 %) R 589,800.00

Extension of oxidation ponds (+ 3000m3 @R80/m3) + lining of + 5000m2 @R130/m2) R 890,000.00

Provision of a bypass from Pond 3 to Pond 7 R 25,000.00


Polishing via a reed bed system (2 279m2) R 400,000.00


Sludge drying beds (480 m2 @R1 800/m2) R 864,000.00

New gravity line, holding tank and pump for irrigation R 150,000.00

Mobile sludge pump (incl pipe work) R 500,000.00

SUBTOTAL R 3,588,800.00

Contingencies (5%) R 179,440.00

Professional fees and disbursements (10%) R 358,880.00

TOTAL R 4,127,120.00

8. CONCLUSION

Despite the good effluent quality data, it is envisaged that the existing works will not have sufficient capacity

to receive and treat the future estimated wastewater flow. Therefore, given the planned new housing

development, the works will have to be upgraded to provide sufficient treatment capacity for the forecasted

increase in flow rate stemming from the new development.

The extension of the pond system as recommended above should be sufficient to provide a final effluent that

could be irrigated on nearby land for luserne production should this option of re-use be adopted. The size

of the ponds, reed bed and sludge drying beds will not exceed the land area that is currently available at the

site of the existing works.

A number of effluent discharge strategies were discussed under Section 6 and Options 1 and 2 are

considered the most feasible. However, both options would require extensive studies and investigations to

be completed as mentioned. It is envisaged that the same studies will have to be conducted regardless of

which option is preferred, and it is recommended that the following studies proceed in order to determine the

way forward:







It is then anticipated that the cost associated with the aforementioned studies would be in the order of

R3,000,000.00 (excl. VAT).

The recommendation of retaining the existing oxidation pond system and only extend to ensure sufficient

treatment capacity is attractive regarding the low operational and maintenance requirements it will have.

Thus, the Municipality will not have to train new process controllers or start using external service providers

for major mechanical and electrical works. This approach, however, can only be confirmed once the studies

above have been completed.


s:\tanya pillay\melkhout - 5 aug\melkhoutfontein report rev 4.docx (tanya pillay) 000/00000/0 : Document Number Rev A : 2019-08-05

APPENDIX 1 - LABORATORY RESULTS



APPENDIX 2 - LAYOUT OF PROPOSED EXTENSIONS

X 3799400

E

X

I

S

T

I

N

G

G

R

A

V

E

L

R

O

A

D

E

X

I

S

T

I

N

G

G

R

A

V

E

L

R

O

A

D

5

5

5

5

5

3

5

3

5

3

5

3

5

3

5

3

5

1

5

1

51

5

7

5

5

5

5

55

51

5

1

5

1

5

3

5

3

5

3

5

3

5

3

5

5

57

5

3

55

5

2

5

2

5

2

5

2

5

2

5

4

5

4

5

4

5

4

5

4

5

6

5

6

5

6

5

2

5

2

5

4

5

4

5

4

58

5

7

WATER LEVEL=53.30

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

NEW SLIDING GATE

6

7

8

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

x

5

5

.0

0

0

5

5

.0

0

0

5

5

.0

0

0

5

5

.0

0

0

A

N

A

E

R

O

B

IC

D

A

M

W

L

=

5

4

.1

9

0

F

L

O

O

R

=

5

1

.2

0

0

E

X

IS

T

IN

G

A

N

A

E

R

O

B

IC

D

A

M

O

U

T

L

E

T

N

E

W

IN

L

E

T

R

E

F

E

R

T

O

D

W

G

H

E

S

R

IV

-4

5

6

-S

0

6

E

X

IS

TIN

G

IN

LE

T

TO

B

E

D

E

M

O

LIS

H

E

D

E

X

IS

T

IN

G

P

U

M

P

L

IN

E

T

O

B

E

R

E

R

O

U

T

E

D

N

E

W

1

1

0

m

m

D

IA

C

L

A

S

S

9

S

E

W

E

R

R

IS

IN

G

M

A

IN

N

E

W

IN

L

E

T

S

T

R

U

C

T

U

R

E

R

E

F

E

R

D

O

D

R

A

W

H

E

S

R

IV

-4

5

6

/S

0

6

55.00

53.60

1.40

1

55.68

54.68

1.00

2

N

E

W

IN

L

E

T

R

E

F

E

R

T

O

D

W

G

H

E

S

R

IV

-4

5

6

-S

0

6

N

E

W

IN

L

E

T

R

E

F

E

R

T

O

D

W

G

H

E

S

R

IV

-4

5

6

-S

0

6

7

3

N

E

W

2

0

0

m

m

D

I

A

C

L

A

S

S

3

4

S

E

W

E

R

G

R

A

V

I

T

Y

M

A

I

N

N

E

W

1

6

0

m

m

D

I

A

C

L

A

S

S

3

4

S

E

W

E

R

G

R

A

V

I

T

Y

M

A

I

N

EXISTING PRIMARY DAM

EXISTING

SECONDARY DAM

EXISTING

TERTIARY DAM

54.42

53.41

1.10

4

54.28

53.14

1.14

5

54.19

53.03

1.16

6

54.27

53.20

1.07

54.09

53.09

1.00

8

54.05

52.91

1.14

9

3

7

.4

6

1

:1

9

7

.1

6

55.84

54.84

1.00

54.19

1:200.70

2

2

.

0

5

1

:

2

0

0

.

4

5

1

:

2

0

0

3

1

.9

6

1

:1

9

9

.7

5

3

.4

8

1

:1

7

4

1

0

.

6

0

1

:

2

0

0

.

7

0

3

4

.

4

1

1

:

1

9

1

.

1

6

515.47m²

V= ±456m³

1

4

0

0

0

7

0

0

0

2

2

2

0

0

2

9

2

0

0

647.9m²

V= ±588m³

SIDE SLOPES 1:2

DEPTH = 3.5m

5

3

0

0

04

2

0

0

0

1

2

6

0

.

0

0

m

²

V

=

±

2

0

0

0

m

³

N

E

W

R

E

E

D

B

E

D

1478.9m²

DEPTH = 0.7m

V= ±1050m³

NEW GATE

2

2

2

6

.

0

0

m

²

V

=

±

0

0

0

m

³

4

2

0

0

0

3

0

0

0

0

8

0

0

0

F

I

N

A

L

E

F

F

L

U

E

N

T

N

E

W

T

E

R

T

I

A

R

Y

P

O

N

D

1

.

5

m

D

E

E

P

1

2

3

4

5

6

7

8558.38m²

V= ±000m³

9

3

2

.

0

m

²

D

E

P

T

H

=

1

.

1

m

V

=

±

1

0

2

5

m

³

9

6

8

.

3

m

²

D

E

P

T

H

=

1

.

1

m

V

=

±

1

0

6

5

m

³

9

6

7

.

9

m

²

D

E

P

T

H

=

1

.

1

m

V

=

±

1

0

6

5

m

³

2658.9m²

DEPTH = 1.5m

V= ±3987m³

TO ACT AS TERTIARY POND

TO BE CONVERTED TO 1 OFF

SECONDARY POND 1.5m DEEP LINED

CHLORINATION

N

E

W

B

Y

P

A

S

S

1

0

0

0

0

8000

3

2

0

0

0

8

0

0

0

8000

8000

1

5

0

0

0

N

E

W

S

L

U

D

G

E

D

R

Y

IN

G

B

E

D

S

8

9

EXISTING

TERTIARY DAM

EXISTING

TERTIARY DAM



APPENDIX 3 – AREA PROPOSED FOR FINAL EFFLUENT IRRIGATION

RE/57/480

66/480

71/480

RE/73/480

92/480 93/480

146/480

149/480

150/480

RE/14

/480

12/480

13/480

133/480

156/480

157/480

158/480

170/480

172/480

174/480

175/480

177/480

179/480

180/480182/480184/480

185/480

187/4

80189/480

190/480

191/480

192/480

194/480195/480

197/480

199/480200/480

202/480

204/480205/480

207/480

209/480210/480

212/480213/480

214/480215/480

218/480

220/480

221/480

223/480

225/480

226/480

228/480

230/480

232/480

233/480

RE/102/480

147/480

138/4

80

137/4

80

RE/56/480

81/480

9/480

69/480

94/480

103/480

151/48

0

152/4

80

171/480

173/480176/480

178/480181/480183/480

186/4

80188/480193/480

196/480

198/480

201/480 203/480

206/480

208/480

211/480

219/480

222/480

224/480

227/480

229/480231/480

142/480

107/480

111/480

159/480

161/480162/480

163/480164/480160/480

134/480

166/480167/480 216/480

217/480

165/480

168/480169/480

140/480

135/480

48/480

RE/630

245/480 249/480

251/4

8025

2/480

253/4

8025

4/480

RE/102/480

141/480

95/480

129/480

148/480

241/4

801/635

RE/635

25/472

33/472

101/4

80RE/154/480

28/47

2

2/472

118/4

80

518

RE/15

/480

RE/65/480

RE/65/480

Source: Esri, DigitalGlobe, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN, and the GIS User Community

MELKHOUTSFONTEINTECHNICAL REPORT

PROJECT

SIGNATURE PR No DATE

SIGNATURE DATE

CONSULTING ENGINEER

CLIENT

PRELIMINARYiX engineers retains the copyright in all intellectual property, inluding

designs and/or documents prepared in terms of this appointment for theproject covered by the appointment. The client may use the designs and/ordocuments for the sole purpose of their intended use on this project only

subject to payment for the design having been received. Use for any otherpurpose, whether or not the design and/or documents have been paid for

constitutes an infringement of copyright, and all rights are reserved.

All dimensions must be verified on site before the works commence.Refer any discrepancies to the Engineer. Copyright reserved

No DATE DESCRIPTIONREVISION SCHEDULE CLIENT

CONSULTANT

ASLA DEVCO

PLAN DESCRIPTION

OWNERSHIPINFORMATION

PROJECT PRODUCED CHECKED

DATE SCALE

PLAN NUMBER REV 00

2019/08/05

31 Allen Drive | Loevenstein | Bellville | Cape Town I 7530 I RSATel: +27 (0)21 912 3000 | Website: www.ixengineers.co.za

GPS: -33.884179, 18.613853

¹

05/08/2019 14:49:20 Printed by: reinhardt.b

Path:

G:\0

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ojects

\3014

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_mxd

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Geo

graph

ic Co

ordina

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GCS

Hart

ebee

sthoe

k 199

4

1:20,000

Melkhoutfontein-1

Melkhoutfontein-2

LegendBoreholes

Irrigation AreaFarm RE/154/480ErvenFarm Portions

OWNER: HESSEQUA MUN

POND SITE



APPENDIX 4 – AQUIFER MAP



APPENDIX 5 – STILBAAI MARINE PROTECTED AREA

HESRIV-489 Services Report -Rev 2enviro-eap.co.za/wp-content/uploads/2020/06/Appendix_L2... · 2020-06-25 · hessequa municipality services report for civil engineering services

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