Guide to the installation of possible rehabilitation and ... · Compiled by: Mr Bertus Fourie (M.Sc. Aquatic Health, Cert. Sci. Nat) Magalies water pipeline: Guide to installation

Magalies water pipeline: Guide to installation of rehab measures 1 of 14 pages

Guide to the installation of possible rehabilitation

and mitigation measures

for

MAGALIES WATER PIPELINE TO

MAROELOESFONTEIN ANDALUSITE MINE

Compiled by: Mr Bertus Fourie (M.Sc. Aquatic Health, Cert. Sci. Nat)


DECLARATION OF INDEPENDENCE

I, Bertus Fourie, declare that -

I am subcontracted as specialist consultant by Galago Environmental cc. for the

aquatic ecosystem delineation.

I will perform the work relating to the application in an objective manner, even if this

results in views and findings that are not favourable to the applicant;

I declare that there are no circumstances that may compromise my objectivity in

performing such work;

I have expertise in conducting the specialist report relevant to this application,

including knowledge of the National Environmental Management Act, 1998 (Act No.

107 of 1998), regulations and any guidelines that have relevance to the proposed

activity; I will comply with the Act, regulations and all other applicable legislation;

I will take into account, to the extent possible, the matters listed in Regulation 8;

I have no, and will not engage in, conflicting interests in the undertaking of the activity;

I undertake to disclose to the applicant and the competent authority all material

information in my possession that reasonably has or may have the potential of

influencing - any decision to be taken with respect to the application by the competent

authority; and - the objectivity of any report, plan or document to be prepared by

myself for submission to the competent authority;

All the particulars furnished by me in this form are true and correct; and

I realise that a false declaration is an offence in terms of Regulation 71 and is

punishable in terms of section 24F of the Act.

Bertus Fourie

SACNASP Reg. No: 300025/13

COPYRIGHT

Copyright to the text and other matter, including the manner of presentation, is the

exclusively the property of the author. It is a criminal offence to reproduce and/or use,

without written consent, any matter, technical procedure, and/or technique contained in this

document. Criminal and civil proceedings will be taken as a matter of strict routine against

any person and/or institution infringing the copyright of the author and/or proprietors.

Bierspruit Crossing: Guide to installation of rehab measures February 2016 3 of 14 pages

TABLE OF CONTENTS

1 GUIDE TO INSTALLING EROSION AND SILTATION PREVENTION

DEVICES – WHERE NEEDED ................................................................................ 7

1.1 RELOCATION OF FAUNA AND FLORA BEFORE AND DURING CONSTRUCTION .......... 7

1.2 SEDIMENT REDUCTION STRUCTURES ............................................................... 8

1.2.1 Bidim Wall (Figure 1) ............................................................................... 8

1.2.2 Fibre rolls ................................................................................................. 8

1.2.3 Straw bales .............................................................................................. 9

1.3 SOIL STABILIZATION ..................................................................................... 10

1.3.1 Hessian or fibre netting .......................................................................... 10

1.3.2 Stake specification ................................................................................. 10

1.3.3 Bentonite application .............................................................................. 11

1.4 RESEEDING METHODS .................................................................................. 11

1.4.1 Seed bed preparation ............................................................................ 11

1.4.2 Replanting of hydrophilic vegetation ...................................................... 11

1.4.3 Seeding of veld rehabilitation grass mix ................................................. 11

1.5 IN-STREAM STRUCTURES .............................................................................. 12

1.5.1 Sand bag walls (trios walls) ................................................................... 12

1.5.2 Spacing of sand bags ............................................................................ 13

1.6 HYDROCARBON POLLUTION PREVENTION ....................................................... 14

FIGURES:

FIGURE 1: THE INSTALLATION OF SEDIMENT TRAPS IN TRIOS ........................................... 8

FIGURE 2: CROSS SECTION OF A PROPERLY INSTALLED STRAW BALE. .............................. 9

FIGURE 3: INSTALLED STRAW BALES SHOWING THE STAKING OF BALES. ......................... 10

FIGURE 4: ILLUSTRATION OF THE PLACEMENT OF SAND BAGS IN THE CHANNEL ............... 12

FIGURE 5: INSTALLED SAND BAGS SHOWING THE HYDROPHYTES REPLANTED AFTER THE

SAND BAG STRUCTURES WERE INSTALLED. ............................................................ 13

FIGURE 6: METHOD TO CALCULATE SPACING OF SAND BAG WALLS ................................ 13

FIGURE 7: TYPICAL HYDROCABON BOOM ..................................................................... 14


Glossary of terms:

Buffer zone- The area of land next to a body of water, where activities such as

construction are restricted in order to protect the water.

Detritus- Decaying organic matter found in the top layer of soil or mixed with wetland

waters; a food source for many small wetland organisms.

Endangered species- Any species of plant or animal that is having trouble surviving and

reproducing. This is often caused by loss of habitat, not enough food, or

pollution. Endangered species are protected by the government in an effort to

keep them from becoming extinct.

Ecosystem- A network of plants and animals that live together and depend on each other

for survival.

Emergent- Soft stemmed plants that grow above the water level.

Erosion- Process in which land is worn away by external forces, such as wind, water, or

human activity.

Freshwater- Water without salt, like ponds and streams.

Gleyed soil- Mineral wetland soil that is or was always wet; this results in soil colours of

grey, greenish grey, or bluish grey.

Habitat- The environment in which an organism lives.

Hydric soil- Soil that is wet long enough for anoxic (oxygenless) conditions to develop. The

water in the soil forces air out. This soil type is found in wetlands.

Hydrocarbon Oils, fuels and paints made using fossil fuels (including crude oils, coal etc.)

Hydrophyte- A plant, which grows in water.

Mesotrophic soil- Soils with a moderate inherent fertility. An indicator of soil fertility is its

base status, which is expressed as a ratio relating the major nutrient cations

(calcium, magnesium, potassium and sodium) found there to the soil's clay

percentage.

Organic material- Anything that is living or was living; in soil it is usually made up of nuts,

leaves, twigs, bark, etc.

Organism- A living thing.

Peat- Organic material (leaves, bark, nuts) that has decayed partially. It is dark brown with

identifiable plant parts, and can be found in peatlands and bogs.

Pollution- Waste, often made by humans, that damages the water, the air, and the soil.

Precipitation- Rain, sleet, hail, snow.

Riparian- Riparian habitat includes the physical structure and associated vegetation of the

areas associated with a watercourse which are commonly characterized by


alluvial soils, and which are inundated or flooded to an extent and with a

frequency sufficient to support vegetation of species with a composition and

physical structure distinct from those of adjacent land areas

Redoximorphic conditions- a soil property, associated with wetness, which results from

the reduction and oxidation of iron and manganese compounds in the soil after

saturation with water and desaturation, respectively. Mottling are common

redoximorphic features of soils.

Runoff- Rainwater that flows over the land and into streams and lakes; it often picks up soil

particles along the way and brings them into the streams and lakes.

Salinity- The amount of salt in water.

Saturation-The condition in which soil contains as much water as it can hold.

Silt- One of three main parts of soil (sand, silt, and clay); silt is small rock particles that are

between .05 mm and .002 mm in diameter.

Submerged aquatic vegetation- Plants that live entirely under water.

Top soil- The top layer of soil; it is full of organic material and good for growing crops.

Water table- The highest level of soil that is saturated by water.

Watershed - All the water from precipitation (rain, snow, etc.) that drains into a particular

body of water (stream, pond, river, bay, etc.)

Wetland- Land which is transitional between terrestrial and aquatic systems where the

water table is usually at or near the surface or the land is periodically covered

with shallow water, and which land in normal circumstances supports or would

support vegetation typically adapted to life in saturated soil.”

Acronyms:

AECO Aquatic

Environmental

Control Officer

ASPT Average Score Per

Taxon

CERM Comprehensive

Ecological Reserve

Methodology

DSS Decision Support

System

DWA Department of

Water Affairs

DWS Department of

water and sanitation

EC Ecological Category

ECO Environmental

control officer

EIS Ecological

Importance and

Sensitivity

EWR Environmental

Water

Requirements


FRAI Fish Response

Assessment Index

FROC Fish reference of

occurrence

GSM Gravel, Sand, Mud

GDARD Gauteng

Department of

Agriculture and

Rural Development

IERM Intermediate

Ecological Reserve

Methodology

IHAS Invertebrate Habitat

Assessment

System

IHI Index of Habitat

Integrity

MIRAI Macro-Invertebrate

Response

Assessment Index

MVIC Marginal Vegetation

in Current

MVOOC Marginal Vegetation

out of Current

NFEPA National Freshwater

Ecosystem Priority

Areas

PES Present Ecological

State

REC Recommended

Ecological Category

REMC Recommended

Ecological

Management Class

RERM Rapid Ecological

Reserve

Methodology

RHP River Health

Programme

SASS5 South African

Scoring System

(Version 5)

SIC Stones in current

SOG Soap, oil and

grease

SOOC Stones out of

current

TPH Total petroleum

hydrocarbons

TWQR Target water quality

range

VEGRAI Vegetation

Response

Assessment Index

Wetland IHI Wetland index of

habitat integrity tool

WMA Water Management

Area

WUL Water use licence

(approved license)

WULA Water use licence

application (license

application)

Bierspruit Crossing: Guide to installation of rehab measures February 2016 7 of 14 pages

1 Guide to installing erosion and siltation prevention devices – where needed

This document should be used during the construction and rehabilitation phase should

certain mitigation measures be needed for the prevention of erosion and siltation.

1.1 Relocation of fauna and flora before and during construction

The relocation of plants before the construction phase commences is of paramount

importance. Most aquatic plants are not for sale in retail nurseries and if found are

expensive. These plants will be needed for the rehabilitation of the construction areas that

will be impacted. Keeping the aquatic plants alive will be a challenge as they need to be

kept in wet containers to promote optimal conditions. If plants are planted in a damaged

state or even in a dormant phase, the re-establishment of these plants will be prolonged

and will have a detrimental effect on the efficiency of the rehabilitation process as well as

the time needed to fill their space in the aquatic ecosystem. The following points are used

as a reference for successful transplants:

It should be attempted to remove aquatic plants with roots and soil intact, so

lessening the impact of the transplant on the plant.

The plants should preferably be placed in waterproof containers to ensure their soil

does not dissolve or break up during transportation to the new temporary site. The

containers should also keep the root system wet to ensure survival of the plants. If

further soil is needed to fill the containers it is advised that soil from the donor site is

used. The use of hessian (or similar) bags is advised as this will allow for the free flow

of water between the surrounding environment and the plant's microclimate. It is

advised to keep monitoring the plants, to ensure they do not rot in the bags, the soil

does not become degraded and the plants do not stand in stagnant water.

The leaves of the aquatic plants must be trimmed back to a length of 100-150 mm to

lessen water loss through evaporation before transplanting.

If possible, the propagation of the plants should be encouraged. The growth of new

plants from rhizomes or stolon’s is encouraged, to increase the number of plants

available for the rehabilitation. Larger clumps of plants can be broken up without too

much damage to the mother plant and planted in the same medium source as the

donor plants.

The use of stolon’s or rhizomes is also advised. These should not be planted where

they are exposed to areas of high water velocity and should be used as fillers


between well-established plants. These should be planted at a depth of 50 mm and

with the right orientation (roots down, stems up) to speed up growth.

Replanting frequency should mimic that found in the natural environment.

Should any species of fauna be found during the construction phase, it is advised that the

species be removed to a safe place in the neighbouring area to ensure the species is not

damaged by the construction activities.

1.2 Sediment reduction structures

1.2.1 Bidim Wall (Figure 1)

Bidim is a geotextile popular in construction works. The walls are made up of Bidim held in

place with y-poles 1 m or one meter (maximum) apart. The Bidim should be placed against

the y-poles and an extra length of about 1 meter should lie on the bottom of the stream

facing upstream, to ensure that no sediment can escape underneath the wall. The height of

the Bidim walls should be 10 cm above the maximum water level. These walls must cover

the whole breadth of the gully and should not allow any water through that has not passed

through the Bidim wall. These sediment barriers must be inspected every week to ensure

they are still functioning. If build-up of sediment occurs then the excess sediment must be

removed. If the barriers are washed away by a flood or damaged in any way their

replacement should occur as soon as possible.

FIGURE 1: THE INSTALLATION OF SEDIMENT TRAPS IN TRIOS

1.2.2 Fibre rolls

Fibre rolls are rolls made of 40 mm x 40 mm chicken wire layered with a geotextile of non-

erosive growing medium. These should be placed horizontal to the flow direction and

should cover the whole length of the channel. Firstly, a trench about 20 cm (about half the

Y-Poles

Flow direction

Bidim

Connection point


height of the fibre roll) should be made in the channel floor and the fibre roll placed in the

trench. The trench should then be filled around the roll and compacted using hand tools.

The roll should then be permanently attached to the gully using wooden stakes, leaving no

more than 50 mm of the stake protruding from the top of the roll. If high flow volumes are

expected, a double stake should be placed on both sides of the roll. These two stakes

should then be tied tightly together using wire.

1.2.3 Straw bales

These should be placed lengthwise across the gully floor. Excavation of soil should be

done to a depth half that of the bales. The bales should then be placed in the trench and

secured using stakes. If any of the bales being used is broken up or starts to break up it

cannot be used since broken bales will break up even further once in free flowing water.

The surrounding soil needs to be replaced and compacted using hand tools. See figure

below.

FIGURE 2: CROSS SECTION OF A PROPERLY INSTALLED STRAW BALE. TAKEN FROM: WWW.RPITT.ENG.UA.EDU/CLASS/EROSIONCONTROL/MODULE8/MODULE8.HTM

http://www.rpitt.eng.ua.edu/Class/Erosioncontrol/Module8/Module8.htm


FIGURE 3: INSTALLED STRAW BALES SHOWING THE STAKING OF BALES.

1.3 Soil stabilization

1.3.1 Hessian or fibre netting

Netting should be used that allows 60% of the surface to be open, allowing for germination

of seeds through the netting. These nets come in widths of 1.3 m and 1.5 m. These should

be adhered to the bank walls with wooden stakes 1.5-2 m apart. The hessian should also

be applied vertically to and lengthwise along the gradient. The hessian should not be

placed as far as the bottom of the gradient or aquatic zone, but should still reach the fibre

rolls. Before installation of the hessian, proper soil preparation by hand using a hoe must

be done to ensure the proper seed beds are formed.

1.3.2 Stake specification

The stakes should all preferably be made from treated wood to prevent antagonistic rot.

The standard length of the stakes should be 800 mm long and 40 mm wide, to ensure a

wide variety of applications. To ensure the stakes are properly embedded they should all

be installed to a minimum of 500 mm below the surface. Any protrusions above any

structures should not exceed 50 mm.


1.3.3 Bentonite1 application

Bentonite supplied in powder form must be applied to the selected areas by means of hand

or mechanical spreading. Application rate of 12-15 kg/m2 is advised. The Bentonite must

then be worked into the soils up to a depth of 100-150 mm using a fork or spade. Once the

Bentonite has been mixed and worked into the soil, light compaction of the soil using a

hand roller (similar to those used on grass rolling) must occur throughout the site. Heavier

rolling can occur around more steeply sloped areas. Planting can then be done prior to the

first wetting of the area as the Bentonite will make working conditions difficult.

1.4 Reseeding methods

1.4.1 Seed bed preparation

Furrows should be made in the soil by hand using hoes. Furrows must be made vertically in

the soil and should be spaced 0.4 m (maximum) apart and at least 10 cm deep. Work

should commence from the top and be conducted downwards and any loose soil and rocks

from the process should be removed to prevent downstream siltation of the river. The beds

should follow the contours of the land and not in any way allow or cause water to collect or

flow in high volumes, which might create erosion gullies. Larger clumps of soil and stones

should be removed to prevent impeding the flow of water. The same procedure should be

followed for sloped and flat areas.

1.4.2 Replanting of hydrophilic vegetation

Due to commercially grown wetland plants not being available, any wetland plants found

(except exotics) must be replanted in a temporary holding area. At the outflows from the

stormwater channels, the planting frequency must be higher than in other areas. The entire

area must be seeded with a mix of endemic grass seeds once all the planting is concluded.

The grass seed mix does not have to be composed of aquatic species and terrestrial grass

species are acceptable, although they must be indigenous. The grass is sown in between

the aquatic plants to ensure stability of the soils until the aquatic plants establish.

1.4.3 Seeding of veld rehabilitation grass mix

This should commence as soon as the hessian is in place. Hand seeding must be done by

professionals only. If any fertilizers are recommended, these should be applied to the wall

area only and not the aquatic ecosystem as this could be detrimental to the health of the

system. If hydroseeding is selected for the seeding process, the hydro-seeders used must

1 Bentonite is available from www.clay.co.za


run for at least 10 minutes before the commencement of the seeding project. This is to

ensure adequate mixing of the seed and water. Water extraction for the hydro seeding from

the stream is not allowed unless authorization is received from the Department of Water

Affairs. A good rehabilitation grass mix can be obtained from Advanced Seed [cf

Google] or Thabakholo Seeds (Pty) Ltd African grass seeds, but must contain

indigenous grass species that are present and conspicuous in the Highveld

grassland.

1.5 In-stream structures

1.5.1 Sand bag walls (trios walls)

Sand bags are usually 50-kg flour (or similar) bags filled with sand. The sand should not be

too fine as this will wash from the bags. River sand is ideal and can be mixed with an

aggregate to reduce the volume of sand required. It is proposed that 3 rows of sand bags

be paced flat and then 2 rows, with a single row on top of them to create a pyramid shaped

cross-section (Figure 4 and Figure 5). The bags must also be placed right up to the edge of

the channel to ensure the wall area of the sand bags is not compromised by incision of the

water around the edge of the sand bags. See section 1.5.2 below for the spacing of the

sand bag walls.

FIGURE 4: ILLUSTRATION OF THE PLACEMENT OF SAND BAGS IN THE CHANNEL


FIGURE 5: INSTALLED SAND BAGS SHOWING THE HYDROPHYTES REPLANTED AFTER THE

SAND BAG STRUCTURES WERE INSTALLED.

1.5.2 Spacing of sand bags

To determine the amount of sand bag wall required for a certain length and slope the

following method is used (Figure 6):

FIGURE 6: METHOD TO CALCULATE SPACING OF SAND BAG WALLS


1.6 Hydrocarbon pollution prevention

Hydrocarbons include all fuels, oils and grease derived from fossil fuels (decomposed

organic materials). To reduce the possibility of these types of pollution, hydrocarbon booms

can be used. These are sausage-like structures filled with a hydrocarbon scrubbing

material. These should be placed in the area below the construction site and should form

part of the spill kits.

FIGURE 7: TYPICAL HYDROCARBON BOOM

Documents

Guide to the installation of possible rehabilitation and ... · Compiled by: Mr Bertus Fourie (M.Sc. Aquatic Health, Cert. Sci. Nat) Magalies water pipeline: Guide to installation