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Mitigation Measures Tool:
Used to identify a suite of possible mitigation measures to reduce risks to aquatic resources.		Relevance of management guideline/mitigation measure
(x = strong relevance; x = some relevance)		Construction Phase
(x = potential relevance to this sector)		Operational phase
(x = potential relevance to this sector)		Useful ReferencesAdditional notes
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ASPECTDESCRIPTION OF MITIGATION MEASURE

Links to numbered references are also provided (See next tab)		Alteration to flow volumes Alteration of patterns of flows (increased flood peaks)Increase in sediment inputs & turbidityIncreased nutrient inputsInputs of toxic contaminants Alteration of acidity (pH) Increased inputs of salts (salinization) Change (elevation) of water temperaturePathogen inputs (i.e. disease-causing organisms)AgricultureIndustryMixed-use/Commercial/Retail/BusinessCivic and socialResidentialOpen spaceTransportation infrastructureService InfrastructureMiningAgricultureIndustryMixed-use/Commercial/Retail/BusinessCivic and socialResidentialOpen spaceTransportation infrastructureService InfrastructureMining
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Site planningEvery effort should be made to avoid potential impacts from the outset of a project (e.g. through careful spatial or temporal placement of elements of infrastructure) to prevent or limit impacts to water resources.xxxxxxxxxxxxxxxxxxxxxxxxxxx
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Site clearingBy minimising the area of soil disturbance and the amount of earthworks required the impact of construction and operations (especially the sedimentation of water bodies) can be greatly reduced.21, 28, 32, 34, 35, 55, 60, 64, 65xxxxxxxxxxxxFor more on minimising earthworks and exposed area surfaces see DWA (2006a) for small scale mining, DWA (2008a) for mine residue deposits, DWA (2008b) for surface mining, DWA (2008d) for all mining types, Sappi (2004), FIEC (2002) and FESA (1999) for forestry and SuSFarMS (2008) for crop farming, USEPA (2006) for construction sites, USEPA (2005) for urban areas, DWAF (unknown date) for general site management and USEPA (2003) for all landuse types. FIEC (2002) also has specific guidelines for soil preparation under specific conditions (soil type, weather, slope).
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Land managementReduced tillage refers to any system that is less intensive and aggressive than conventional tillage. The number of operations is decreased compared to conventional tillage, or a tillage implement that requires less energy per unit area is used to replace a typically used implement. The term is sometimes used to imply conservation tillage; however, for a system to be considered a conservation tillage system, 30% of the soil surface must be covered with residue after planting.11, 66xxxFor more on conservation tillage see Delin et al. (2002).
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Land managementDestumping is the process of removing the stumps of felled trees and has the potential for high environmental impacts, through sedimentation especially if stumps are uprooted.35xxFor specific guidelines on destumping under different conditions see FIEC (2002).The order of preference of destumping methods is: 1. Chemical 2. Grinding 3. V-blading and 4. uprooting to minimise the environmental impact.35
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Site clearingClearing and grading should occur only where absolutely necessary to build and provide access to structures and infrastructure. Clearing should be done immediately before construction, rather than leaving soils exposed for months or years.65xxxxxxxxxxxxFor guidelines on minimising land-clearing/ grading see USEPA (2005).
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Site clearingWhere possible, plants should be cut down to ground level instead of being removed completely to stabilise the soil during land-clearing operations.32xxxxxxxxxxx
11
Site clearingAreas on construction sites are often unnecessarily cleared. Site fingerprinting involves clearing only those areas essential for conducting construction activities, leaving other areas undisturbed. The proposed limits of land disturbance should be physically marked off to ensure that only the land area required for buildings, roads, and other infrastructure is cleared. Existing vegetation, especially vegetation on steep slopes, should be avoided and preserved through fencing, signage, and site plan notations.65xxxxxxxxxxxxFor guidelines on site fingerprinting see USEPA (2005).
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Site clearingConstruction phasing (sequencing) is a process by which only a portion of the site is disturbed at any one time according to a planned schedule to complete the needed building in that phase. Other portions of the site are not cleared and graded until exposed soils from the earlier phase have been stabilized and the construction is nearly completed.64, 65xxxxxxxxxxxFor guidelines on how to phase activities to minimise soil exposure see USEPA (2005) and USEPA (2006) specifically for construction management.
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Timber harvestingNo more than one third of the catchment size should be clearfelled within a two year period and clearfellings should be separated sufficiently so that unfelled areas act as sediment traps as well as escape routes for animals.35xxFor more clearfelligns management guidelines consult FIEC (2002).
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Timber harvestingTactical harvest plans are typically done for a 3-5 year planning cycle. Systems and equipment choices must take into consideration the topography, soil and weather conditions of the area to reduce potential impacts.35xxConsult FIEC (2002), Sappi (2004) OR FESA (1999) for detailed guidelines on how to minimise the environmental impact during harvesting operations.
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Timber harvestingAnnual plans of operations (APOs) must see to it that large continuous tracts of land are not harvested.35xx
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Land managementHarvesting should take place in the appropriate season to avoid unnecessary damage to the water resources.35xx
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Landing sites and depotsTo reduce erosion/sedimentation landings and depots should be as small as practically possible, only placed on slopes of 3-6% and utilise sediment traps.35xxxFor more guidelines on the management of landings and depots see FIEC (2002).
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Runoff controlRunoff from disturbed areas (such as landing/depot areas, extraction routes, gravel pits, temporary and unpaved roads) must be directed to silt traps (silt fences, sandbags etc (See below) to remove sediment and reduce the sedimentation of the water bodies.6, 11, 14, 17,18, 19, 21, 22, 28, 32, 34, 35, 44, 52, 55, 57, 64, 65, 66xxxxxxxxxxxxxxxxxxxFor more guidelines on the use of filter strips see Sappi (2004), FIEC (2002) or FESA (1999) for forestry. DOW (2006) and SuSFarMS (2008) for crop farming, MacFarlane et al. (2007), USEPA (2006), DWAF (unknown) for construction sites, USEPA (2005) for urban areas, SANRAL (2009b) for roads, DWA (2006a) for small scale mining, DWA (2008a) for mine residue deposits, DWA (2008b) for surface mining, DWA (2008c) for underground mining, DWA (2008d) for all mining types and USEPA (2003) for all landuse types.
19
Land managementSpread stockpiled topsoil over obsolete depots, install proper drainage and revegetate to reduce the environmental impact of the site. 34, 35xxx
20
Land managementExtraction routes are highly prone to erosion, so should be protected after use using slash that is laid parallel to the contour (making good contact with the ground).35, 60xxFor more guidelines on the management of extraction routes see FIEC (2002).
21
Land managementRuts and skid trails should be rehabilitated. This can be done using slash to stabilise the soil and revegetation.35xxFor guidelines on how to rehabilitate old extraction routes see FIEC (2002).
22
Borrow / Gravel pitsBy utilising the correct drainage control methods erosion can be reduced during the period during which gravel pits are being actively used. Also, by storing topsoil (and other soil layers separately) pits can be filled and revegetated on closure.27, 35xxxxxxxFor more guidelines on the optimal use and rehabilitation of gravel pits see FIEC (2002). For guidelines on appropriate drainage construction see Appendix 4 in DWA (2006a) as well as Appendix 1 in SuSFarMS (2008).
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Road Construction & MaintenanceThe environmental impact of unpaved roads (especially in rural/ agricultural areas) can be reduced by following simple best practice guidelines: construction parallel to the contour, avoiding slopes that exceed 1 to 10 and reducing the number of water body crossings to reduce erosion the sedimentation of water resources as well as the contamination of water by toxins from vehicles.17, 21, 28, 31, 34, 35, 55, 64xxxxxxxxxxxFor guidelines on the BMP for unpaved roads see SANRAL (2009b) and DNREA (2006), Walker et al. (2000) and Cummings (1999). Specifically for forestry purposes also see FIEC (2002), Sappi (2004) and FESA (1999). For crop-farming see SuSFarMS (2008), DOW (2006) and Devlin et al. (2002). For mining see DWA (2008f, 2008a) as well as DWA 2008b for surface mines.
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Road Construction & MaintenanceRoads and railways should be placed on or in close proximity to topographical features with "positive cardinal points" such as saddles, ridge-tops, natural benches and flatter slopes to reduce earthmoving requirements. Similarly features with "negative cardinal points" such as steep slopes, cliffs, large rocks or sites prone to landslides, should be avoided .35xxxxxxxxxxxConsult FIEC (2002) for further guidance on road planning.
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Road Construction & MaintenanceRoads should typically not be placed within 10m of a water body/wetland (except where they cross) as they are a major source of sedimentation. So where possible they should be re-routed, taking care that the re-routing does not cause damage greater than that caused by the road in the first place.35xxxxxxxxxxx
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Watercourse-crossingsBridges should be constructed so that the banks of the water body are stabilised and do not erode or fail completely.11xxxxxxxxxxFor guidelines on the environmentally sound construction of bridges see Chanson (2000). Specifically for forestry bridges see FIEC (2002) and FESA (1999) and Devlin et al. (2002) for crop farming. For guidelines on bridge-drainage see SANRAL (2009b) and DNREA (2006).
27
Watercourse-crossingsDrifts are low-water bridges built below the highest flood level and are often submerged but still enable vehicles to cross a watercourse. Drifts with heavy traffic have a large negative environmental affect, so a bridge would be more suitable for routes with heavy traffic. This reduces soil as well as contaminants from the vehicles washing into the water body.11, 34, 35, 60xxxxxxxxxxxFor guidelines on building bridges instead of drifts in areas with heavy traffic see Chanson (2000). See FIEC (2002) and FESA (1999) for bridge building in forestry plantations and Devlin et al. (2002) for crop farming.
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Watercourse-crossingsDrifts are only suitable for low usage roads, as they have high environmental impacts (sedimentation and pollution from crossing vehicles) and do not enable crossing during flood events. They should be built below straight sections of watercourses, cross at right angles to it and only where the streambed and approach are stable.31, 35xxxxxxxxxxxFor guidelines on the BMPs of road construction and management (including water body-crossings) see SANRAL (2009b),DNREA (2006), Walker et al. (2000) and Cummings (1999). Specifically for forestry purposes also see FIEC (2002), Sappi (2004) and FESA (1999). For crop-farming see SuSFarMS (2008), DOW (2006) and Devlin et al. (2002). For mining see DWA (2008f, 2006b) as well as DWA 2008b for surface mines.
29
Watercourse-crossingsWhen constructing infrastructure crossing a water body use excavators instead of bulldozers to reduce sedimentation and consolidate the entry and exit points to reduce scouring.31, 35xxxxxxxxxxFor guidelines on the BMPs of road construction and management see SANRAL (2009b), DNREA (2006), Walker et al. (2000) and Cummings (1999). Specifically for forestry purposes also see FIEC (2002), Sappi (2004) and FESA (1999). For crop-farming see SuSFarMS (2008), DOW (2006) and Devlin et al. (2002). For mining see DWA (2008f, 2006b) as well as DWA 2008b for surface mines.
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Watercourse-crossingsAbutments are fortified structures (concrete, rock etc) that prevent slope failure or erosion (especially abutment fill, which commonly occurs where bridges are built). They simply hold the bank substrate in place, concealing from the flowing water.35xxxxxxxxxxFor guidelines on environmentally sound bridge building see USEPA (2003), Chanson (2000) and Cummings (1999). Specifically for forestry purposes also see FIEC (2002), Sappi (2004) and FESA (1999). For crop-farming see SuSFarMS (2008), DOW (2006) and Devlin et al. (2002). For mining see DWA (2008f, 2006b) as well as DWA 2008b for surface mines.
31
Watercourse-crossingsKerbs prevent material from sliding off the side of a bridge into the water body and should direct water to the edges, where the runoff is passed trough filter strips before entering the waterbody.35xxxxxxxxxxFor guidelines on environmentally sound bridge building see Chanson (2000) and Cummings (1999).Specifically for forestry purposes also see FIEC (2002), Sappi (2004) and FESA (1999). For crop-farming see SuSFarMS (2008), DOW (2006) and Devlin et al. (2002). For mining see DWA (2008f, 2006b) as well as DWA 2008b for surface mines.
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Road Construction & MaintenanceThe road density in forestry areas can be optimised according to the terrain and extraction routes and can also be linked to other compartments to minimise financial and environmental costs.35xxFor guidelines on environmentally sound road planning see SANRAL (2009a, 2009c) and Cummings (1999). Specifically for forestry purposes also see FIEC (2002), Sappi (2004) and FESA (1999). For crop-farming see SuSFarMS (2008), DOW (2006) and Devlin et al. (2002). For mining see DWA (2008f, 2006b) as well as DWA 2008b for surface mines.
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Road Construction & MaintenanceRoutes should not follow the course of a river to reduce construction and maintenance costs, drainage requirements and ultimately the sediment load.35xxxxxxxxxxFor guidelines on environmentally sound road planning see SANRAL (2009a, 2009c) and Cummings (1999). Specifically for forestry purposes also see FIEC (2002), Sappi (2004) and FESA (1999). For crop-farming see SuSFarMS (2008), DOW (2006) and Devlin et al. (2002). For mining see DWA (2008f, 2006b) as well as DWA 2008b for surface mines.
34
Road Construction & MaintenanceIf a road is perpendicular to the contour, it channels runoff, causing the creation of gulleys and rills. A longitudinal gradient ≥12 % should not be exceeded for more than 50m.35xxxxxxxxxxFor guidelines on environmentally sound road planning see SANRAL (2009a, 2009c) and Cummings (1999). Specifically for forestry purposes also see FIEC (2002), Sappi (2004) and FESA (1999). For crop-farming see SuSFarMS (2008), DOW (2006) and Devlin et al. (2002). For mining see DWA (2008f, 2006b) as well as DWA 2008b for surface mines.
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Road Construction & MaintenanceOn roads / tracks with a gradient >12% it may be necessary to apply special surface protection measures (including importing crushed rock or gravel) to prevent erosion of the surface layer.31, 35xxxxxxxxxxFor guidelines on the use of road surface protection see DNREA (2006), USEPA (2003), Walker et al. (2002) and Cummings (1999). Specifically for forestry purposes also see FIEC (2002), Sappi (2004) and FESA (1999). For crop-farming see SuSFarMS (2008), DOW (2006) and Devlin et al. (2002). For mining see DWA (2008f, 2006b) as well as DWA 2008b for surface mines.
36
Road Construction & MaintenanceSteep roads (> 12% gradient), are major sources of erosion, as they concentrate and channel runoff, which causes the formation of gullies, rills and road degradation. If they are essential then erosion protection mechanisms MUST be installed.35xxxxxxxxxxFor guidelines on environmentally sound road planning Cummings (1999). Specifically for forestry purposes also see FIEC (2002), Sappi (2004) and FESA (1999). For crop-farming see SuSFarMS (2008), DOW (2006) and Devlin et al. (2002). For mining see DWA (2008f, 2006b) as well as DWA 2008b for surface mines.
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Road Construction & MaintenanceGrass is very efficient at stabilising soil and low-usage unpaved roads should be grassed to reduce erosion.31, 35xxxxxxxxxxFor guidelines on the use of grass to protect the road surface see USEPA (2003), Walker et al. (2002) and Cummings (1999). Specifically for forestry purposes also see FIEC (2002), Sappi (2004) and FESA (1999). For crop-farming see SuSFarMS (2008), DOW (2006) and Devlin et al. (2002). For mining see DWA (2008f, 2006b) as well as DWA 2008b for surface mines.
38
Road Construction & MaintenanceRoads should be constructed on flatter terrain to reduce erosion as well as construction and maintenance costs.35xxxxxxxxxxFor guidelines on environmentally sound road planning see SANRAL (2009a, 2009c) and Cummings (1999). Specifically for forestry purposes also see FIEC (2002), Sappi (2004) and FESA (1999). For crop-farming see SuSFarMS (2008), DOW (2006) and Devlin et al. (2002). For mining see DWA (2008f, 2006b) as well as DWA 2008b for surface mines.
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Road Construction & MaintenanceOn slopes > 60% a full bench should be constructed and the end hauling method (NOT the fill and cut method) used to construct it.31, 35xxxxxxxxxxFor guidelines on the BMPs of road construction see SANRAL (2009b) and DNREA (2006), Walker et al. (2000) and Cummings (1999). Specifically for forestry purposes also see FIEC (2002), Sappi (2004) and FESA (1999). For crop-farming see SuSFarMS (2008), DOW (2006) and Devlin et al. (2002). For mining see DWA (2008f, 2006b) as well as DWA 2008b for surface mines.
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Borrow / Gravel pitsTo reduce borrow pits and soil dumping (both sources of sediment) cut and fill should be balanced as best as possible and the distance for moving cut and fill should be minimised.35xxxxxxxFor guidelines on balancing the cut and fill method see Cummings (1999). Specifically for forestry purposes also see FIEC (2002), Sappi (2004) and FESA (1999). For crop-farming see SuSFarMS (2008), DOW (2006) and Devlin et al. (2002). For mining see DWA (2008f, 2006b) as well as DWA 2008b for surface mines.
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Road Construction & MaintenanceWater on the road/railway etc should be diverted away as quickly as possible, to minimise the amount of water running directly from the road into the water body. The drainage must lead the water to vegetated filter strips, which remove particles and contaminants from the water.31, 34, 35, 52xxxxxxxxxxxxxxFor guidelines on the BMPs of road drainage see SANRAL (2009b), DNREA (2006), USEPA (2003), Walker et al. (2000) and Cummings (1999). Specifically for forestry purposes also see FIEC (2002), Sappi (2004) and FESA (1999). For crop-farming see SuSFarMS (2008), DOW (2006) and Devlin et al. (2002). For mining see DWA (2008f, 2006b) as well as DWA 2008b for surface mines.
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Road Construction & MaintenanceHaving more frequent drains on the approach to a water body ensures that the least amount of water is discharged directly into the water body and reduced sediment loading.31, 34, 35, 52xxxxxxxxxxxxxFor guidelines on the BMPs of road drainage see SANRAL (2009b), DNREA (2006), Walker et al. (2000) and Cummings (1999). Specifically for forestry purposes also see FIEC (2002), Sappi (2004) and FESA (1999). For crop-farming see SuSFarMS (2008), DOW (2006) and Devlin et al. (2002). For mining see DWA (2008f, 2006b) as well as DWA 2008b for surface mines.
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Road Construction & MaintenanceRoads that are not absolutely necessary should be rehabilitated (using stockpiled topsoil) and revegetated.27, 35xxxxxxxxxxxxxFor guidelines on the rehabilitation of roads see USEPA (2003) and Cummings (1999). Specifically for forestry areas also see FIEC (2002), Sappi (2004) and FESA (1999). For crop-farming see SuSFarMS (2008), DOW (2006) and Devlin et al. (2002). For mining see DWA (2008f, 2008e, 2008b and 2006b).
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Road Construction & MaintenanceCulverts channel runoff underneath roads, railways, banks etc. The water velocity is slowed and the sediment deposited in the outlet, where it then passes through a constructed sediment trap (made of logs, rocks, branches or concrete to remove the remaining sediments before it is discharged to a suitable discharge area or water body. 31, 52xxxxxxxxxxxxxFor guidelines on the use of culverts see SANRAL (2009b), DNREA (2006), Walker et al. (2000), Chanson (2000) and Cummings (1999). Specifically for forestry purposes also see FIEC (2002), Sappi (2004) and FESA (1999). For crop-farming see SuSFarMS (2008), DOW (2006) and Devlin et al. (2002). For mining see DWA (2008f, 2006b) as well as DWA 2008b for surface mines.
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Watercourse-crossingsRiver/ stream crossings can cause severe environmental degradation. To minimise this crossings should be constructed at right angles to the watercourse, approach it at a low angle and use gabions, concrete or hyson cells to protect sidewalls, embankments and the riverbed.17, 34, 35, 44, 55xxxxxxxxxxxxxFor guidelines on the use of water body-crossings see SANRAL (2009b), DNREA (2006), USEPA (2003), Chanson (2000) and Cummings (1999). For forestry areas specifically see FIEC (2002), Sappi (2004) and FESA (1999). For crop-farming see SuSFarMS (2008), DOW (2006) and Devlin et al. (2002). For mining see DWA (2008f, 2006b) as well as DWA 2008b for surface mines. For guidelines on minimising the impact of pipeline crossings see DWAF (unknown) and MacFarlane et al. (2007).
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Road Construction & MaintenanceIf possible, existing watercourse-crossings should be used during activities to eliminate the impacts of constructing more crossings.44xxxxxxxxxxFor guidelines on the use of water body-crossings see SANRAL (2009b), DNREA (2006), Chanson (2000) and Cummings (1999). For forestry areas specifically see FIEC (2002), Sappi (2004) and FESA (1999). For crop-farming see SuSFarMS (2008), DOW (2006) and Devlin et al. (2002). For mining see DWA (2008f, 2006b) as well as DWA 2008b for surface mines. For guidelines on minimising the impact of pipeline crossings see DWAF (unknown) and MacFarlane et al. (2007).
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Watercourse-crossingsWhen a wetland must be crossed ( by a road, pipeline etc) it must be constructed perpendicular to it to minimise the zone of impact.32xxxxxxxxxxFor guidelines on the use of wetland crossings see SANRAL (2009b), DNREA (2006), Chanson (2000) and Cummings (1999). For forestry areas specifically see FIEC (2002), Sappi (2004) and FESA (1999). For crop-farming see SuSFarMS (2008), DOW (2006) and Devlin et al. (2002). For mining see DWA (2008f, 2006b) as well as DWA 2008b for surface mines. For guidelines on minimising the impact of pipeline crossings see DWAF (unknown) and MacFarlane et al. (2007).
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Watercourse-crossingsAfter watercourse-crossings have been constructed the disturbed areas must be engineered to coincide as close a possible to the original river/ stream contour. This reduced the potential for instream erosion and bank failure.32xxxxxxxxxxFor guidelines on reinstating the natural contour of watercourses at crossings see DWAF (unknown).
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Stream channel stabilizationStream channel stabilization means stabilizing the channel of a stream with suitable structures to prevent erosion or siltation of the channel. A channel is considered stable if, the channel bottom remains essentially at the same elevation over long periods of time. Stream channel stabilization methods include modifying the channel capacity, channel armouring (e.g. riprap lining), providing channel crossings for livestock, and vegetating (either by seeding or planting the channel to prevent erosion).66xxxxxxxxxxFor more on Stream channel stabilisation see Chason (2009), USEPA (2003) and Cummings (1999). For forestry areas specifically see FIEC (2002), Sappi (2004) and FESA (1999). For crop-farming see SuSFarMS (2008), DOW (2006) and Devlin et al. (2002). For mining see DWA (2008f, 2006b) as well as DWA 2008b for surface mines. For guidelines on minimising the impact of pipeline crossings see DWAF (unknown) and MacFarlane et al. (2007).
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Stream bank protectionStream bank protection helps to prevent stream bank erosion. Stream bank protection methods are essentially the same as for 'stream channel stabilization'. They include modifying the channel capacity, channel armouring, providing channel crossings for livestock, and vegetating.66xxxxxxxxxxFor more on Stream bank protection see Chason (2009), USEPA (2003) and Cummings (1999). For forestry areas specifically see FIEC (2002), Sappi (2004) and FESA (1999). For crop-farming see SuSFarMS (2008), DOW (2006) and Devlin et al. (2002). For mining see DWA (2008f, 2006b) as well as DWA 2008b for surface mines. For guidelines on minimising the impact of pipeline crossings see DWAF (unknown) and MacFarlane et al. (2007).
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Watercourse-crossingsWhere watercourse-crossings (of pipes etc) are being constructed. Sandbags must be placed across the trench before the riparian zone to minimise sedimentation of the watercourse.32xxxxxxxxxxSee DWAF (unknown).
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Watercourse-crossingsDuring the completion of construction/activities in aquatic environments (e.g. crossings, dredged areas), natural material (coarse in the case of river/ stream beds) should be used to re-surface the bed of the aquatic area to re-instate habitat for aquatic organisms.44xxxxxxxxxxFor guidelines on the reinstatement of natural materials to the water-course see Cummings (1999). For forestry areas specifically see FIEC (2002), Sappi (2004) and FESA (1999). For crop-farming see SuSFarMS (2008), DOW (2006) and Devlin et al. (2002). For mining see DWA (2008f, 2006b) as well as DWA 2008b for surface mines. For guidelines on minimising the impact of pipeline crossings see DWAF (unknown) and MacFarlane et al. (2007).
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Land managementWhen trenches are dug (e.g. for pipelines) water must not be allowed to flow along it but must be routed diagonally across it to reduce erosion and sedimentation.32xxxxxxxxxxFor guidelines on trench-drainage see DWAF (unknown) as well as DWA (2008f, 2008b, 2006b) for mining. Specifically for forestry areas see FIEC (2002), Sappi (2004) and FESA (1999). For crop-farming see SuSFarMS (2008), DOW (2006) and Devlin et al. (2002).
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Watercourse-crossingsFor small rivers/ streams a small dam constructed out of sandbags can be built upstream of the crossing construction (e.g. for pipeline) and the water rerouted to the downstream side of the construction and returned at a similar rate as the rate that it enters the dam.32xxxxxxxxxxFor guidelines on the use of temporary dams see DWAF (unknown).
55
Road Construction & MaintenanceThe constructed surface (road/ railway/pipeline etc) must be built above the natural ground level to facilitate efficient drainage, to minimise surface degradation/ erosion.31, 35xxxxxxxxxxFor guidelines on drainage BMPs see SANRAL (2009b), DNREA (2006), Walker et al. (2000) and Cummings (1999) for roads. For forestry see FIEC (2002), Sappi (2004) and FESA (1999). For crop-farming see SuSFarMS (2008), DOW (2006) and Devlin et al. (2002) and for mining see DWA (2008f, 2008b, 2006b).
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Site clearingWhen excavated areas are backfilled the surface must be level with the surrounding land surface, to minimise soil erosion from the areas when the excavation is complete.44xxxxxxxxxxxFor guidelines on minimising the impact from backfill areas see Macfarlane et al. (2007). or forestry see FIEC (2002), Sappi (2004) and FESA (1999). For crop-farming see SuSFarMS (2008), DOW (2006) and Devlin et al. (2002) and for mining see DWA (2008f, 2008e, 2008c, 2008b, 2008a, 2007a, 2006b and 2006a).
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Watercourse-crossingsThe level of the streambed must not be lower than it's original level when construction across the channel takes place, as this would cause erosion of the upstream.32xxxxxxxxxxFor guidelines on instream construction see Chason (2009), USEPA (2003) and Cummings (1999) for transport-crossings. For forestry areas specifically see FIEC (2002), Sappi (2004) and FESA (1999). For crop-farming see SuSFarMS (2008), DOW (2006) and Devlin et al. (2002). For mining see DWA (2008f, 2006b) as well as DWA 2008b for surface mines. For guidelines on minimising the impact of pipeline crossings see DWAF (unknown) and MacFarlane et al. (2007).
58
Road Construction & MaintenanceThe camber of the road must be sufficient to facilitate water runoff so that road degradation/ erosion is reduced.31, 35xxxxxxxxxxFor guidelines on road camber see SANRAL (2009b), DNREA (2006), Walker et al. (2000)and Cummings (1999). Specifically for forestry purposes also see FIEC (2002), Sappi (2004) and FESA (1999). For crop-farming see SuSFarMS (2008), DOW (2006) and Devlin et al. (2002). For mining see DWA (2008f, 2006b) as well as DWA 2008b for surface mines.
59
Watercourse-crossingsWaterbody crossings must be regularly checked to ensure they are not being degraded or causing degradation and that openings (under a bridge or at a culvert opening) are kept clear. This minimises erosion.21, 35xxxxxxxxxxxxxxxxxxxFor guidelines on the maintenance of bridges see SANRAL (2009b), DNREA (2006) and Chanson (2000). Specifically for forestry bridges see FIEC (2002) and FESA (1999) and for crop-farming see Devlin et al. (2002).
60
Site clearingTo prevent unnecessary sediment loading of waterbodies the construction of infrastructure should be carried out in the months without high rainfall.35xxxxxxxxxx
61
Borrow / Gravel pitsDrains of suitable design (so that they do not erode) should carry water from the borrow pit, over the fill area to a filter strip. This is a vegetated (or otherwise specially designed) piece of land that removes sediment and other contaminants from the water prior to it entering the waterbody.35xxxxxxxFor guidelines on the drainage and filtering of runoff from borrow pits see FIEC (2002), Sappi (2004) and FESA (1999), especially for forestry. For crop-farming see SuSFarMS (2008), DOW (2006) and Devlin et al. (2002) and for mining see DWA (2008f, 2008e, 2008c, 2008b, 2008a, 2007a, 2006b and 2006a).
62
Borrow / Gravel pitsWhen they become redundant borrow pits should be rehabilitated OR turned into a permanent water body within 2 years of becoming redundant to reduce the environmental impact.27, 34, 35xxxxxxxFor guidelines on the rehabilitation of borrow pits see FIEC (2002), Sappi (2004) and FESA (1999) in forestry areas. For crop-farming see SuSFarMS (2008), DOW (2006) and Devlin et al. (2002) and for mining see DWA (2008f, 2008e, 2008c, 2008b, 2008a, 2007a, 2006b and 2006a).
63
Site drainageEnsuring that a suitable drainage system is in place before construction on a site takes place is important to keep the area as dry as possible and thereby reducing the amount of erosion.31, 35xxxxxxxxxxFor guidelines on drainage BMPs see SANRAL (2009b), DNREA (2006), Walker et al. (2000) and Cummings (1999) for roads. For forestry see FIEC (2002), Sappi (2004) and FESA (1999). For crop-farming see SuSFarMS (2008), DOW (2006) and Devlin et al. (2002) and for mining see DWA (2008f, 2008b, 2006b).
64
Site clearingExcavators should be used instead of bulldozers in areas sensitive to erosion (e.g. steep areas and unstable soils).35xxxxxxxxxx
65
Site clearingStabilise fills using the bench compaction method¹ especially on unstable soils or steep slopes.35xxxxxxxxxxFor guidelines on bench compaction methods see Cummings (1999) for roads. For forestry see FIEC (2002), Sappi (2004) and FESA (1999). For crop-farming see SuSFarMS (2008), DOW (2006) and Devlin et al. (2002) and for mining see DWA (2008f, 2008b, 2006b).
66
Road Construction & MaintenanceA water bar diverts water flowing down a surface (e.g. road) to one side. This reduces the volume of water that flows down the surface and the subsequent erosion that occurs.31, 35xxxxxxxxxxxxxxxxxxFor guidelines on drainage BMPs see SANRAL (2009b), DNREA (2006), Walker et al. (2000) and Cummings (1999) for roads. For forestry see FIEC (2002), Sappi (2004) and FESA (1999). For crop-farming see SuSFarMS (2008), DOW (2006) and Devlin et al. (2002) and for mining see DWA (2008f, 2008b, 2006b).
67
Site managementAll natural waterways within a development site should be clearly identified before construction activities begin. Sediment control practices (e.g. check dams, see below) may be needed to stabilize drainageways and retain sediment on-site.31, 65xxxxxxxxxxFor guidelines on drainageway stabilization and protection see SANRAL (2009b), DNREA (2006), Walker et al. (2000) and Cummings (1999) for roads. For construction sites see USEPA (2006), for urban areas see USEPA (2005). For forestry see FIEC (2002), Sappi (2004) and FESA (1999). For crop-farming see SuSFarMS (2008), DOW (2006) and Devlin et al. (2002) and for mining see DWA (2008f, 2008b, 2006b).
68
Site drainageHigh runoff velocity and volume often cause erosion in newly constructed or existing runoff conveyance channels. If the runoff during or after construction will cause erosion in a channel, the channel should be lined or flow control practices should be installed. The first choice of lining is grass or sod because they reduce runoff velocities and provide water quality benefits through filtration and infiltration. If the velocity in the channel would erode the grass or sod, turf reinforcement mats, riprap, concrete, or gabions can be used.31, 65xxxxxxxxxxxFor guidelines on drain lining see SANRAL (2009b), DNREA (2006), Walker et al. (2000) and Cummings (1999) for roads. For construction sites see USEPA (2006), for urban areas see USEPA (2005). For forestry see FIEC (2002), Sappi (2004) and FESA (1999). For crop-farming see SuSFarMS (2008), DOW (2006) and Devlin et al. (2002) and for mining see DWA (2008f, 2008b, 2006b).
69
Site drainageHigh water velocity greatly increases the erosion risk so drains that convey such water should contain energy brakes (such as lining with stones, concrete, grass or gabions) to reduce the water velocity and therefore erosion.31, 35xxxxxxxxxxxFor guidelines on the use of energy brakes consult SANRAL (2009b), DNREA (2006), Walker et al. (2000) and Cummings (1999) for roads. For forestry see FIEC (2002), Sappi (2004) and FESA (1999). For crop-farming see SuSFarMS (2008), DOW (2006) and Devlin et al. (2002) and for mining see DWA (2008f, 2008b, 2006b).
70
Site drainageThe area where water disperses out of a drain must be suitable for such and must not be susceptible to erosion.31, 35xxxxxxxxxFor guidelines on areas suitable for dispersing stormwater runoff see SANRAL (2009b), DNREA (2006), Walker et al. (2000) and Cummings (1999) for roads. For urban areas see USEPA (2005). For forestry see FIEC (2002), Sappi (2004) and FESA (1999). For crop-farming see SuSFarMS (2008), DOW (2006) and Devlin et al. (2002) and for mining see DWA (2008f, 2008b, 2006b).
71
Site drainageMitre drains convey water from side drains onto land where the water can disperse (i.e. away from the constructed surface). They should be constructed where wash can be expected.11, 31, 35xxxxxxxxxFor guidelines on using mitre drains see SANRAL (2009b), DNREA (2006), Walker et al. (2000) and Cummings (1999) for roads. For urban areas see USEPA (2005). For forestry see FIEC (2002), Sappi (2004) and FESA (1999). For crop-farming see SuSFarMS (2008), DOW (2006) and Devlin et al. (2002) and for mining see DWA (2008f, 2008b, 2006b).
72
Road Construction & MaintenanceCatch drains receive sheet runoff from the road and should be placed on the top side of a cut so that erosion on the face side of the cut is reduced.31, 35xxxxxxxxxFor guidelines on the use of catch drains see (2009b), DNREA (2006), Walker et al. (2000) and Cummings (1999) for roads. For urban areas see USEPA (2005) and for construction sites see USEPA (2006). For forestry see FIEC (2002), Sappi (2004) and FESA (1999). For crop-farming see SuSFarMS (2008), DOW (2006) and Devlin et al. (2002) and for mining see DWA (2008f, 2008b, 2006b).
73
Site drainageFall (the downward slope of a drain) must be present to cause water to flow down the drain otherwise problems of overflow and blockages are caused that lead to erosion.52xxxxxxxxxFor guidelines on how to construct drains with adequate fall consult SANRAL (2009b).
74
Erosion/ sedimentation controlExposed slopes are highly prone to erosion, so drainage control features such as earth dikes, perimeter dikes/swales, diversions ( see below) can be used to intercept and convey runoff from above disturbed areas to suitable dispersal areas or drainage systems. This helps to reduce the sedimentation from exposed areas. 31, 65xxxxxxxxxxFor guidelines on the interception of runoff from exposed slopes see (2009b), DNREA (2006), Walker et al. (2000) and Cummings (1999) for roads. For urban areas see USEPA (2005) and for construction sites see USEPA (2006). For forestry see FIEC (2002), Sappi (2004) and FESA (1999). For crop-farming see SuSFarMS (2008), DOW (2006) and Devlin et al. (2002) and for mining see DWA (2008f, 2008b, 2006b).
75
Road Construction & MaintenanceWhoa boys are shallow channels dug across a road, with the fill material being used to make a bank on the downside of the slope. These direct runoff off a road, reducing erosion.12xxxxxxxxxFor guidelines on the use of whoa boys see DNREA (2006).
76
Soil stabilizationGullies and other areas of active erosion should be stabilised (using catch water drains, raising headwalls or providing protective measures including grassing, stone pitching, concrete paving or gabions/ mattresses) and rehabilitated to minimise sediment entering the aquatic resource from these sources.13, 14, 27xxxxxxxxxxxxxxxxxxx
77
Site drainageClear drains to avoid blockages and reduce the potential for surface degradation and erosion.35xxxxxxxxSee SANRAL (2009b) for BMPs on drain clearing.
78
Road Construction & MaintenanceSlash and debris from harvesting operation should be cleared from road drains and pipes to avoid blockages and prevent overflows that cause erosion. 65xx
79
Soil stabilizationStabilization practices (e.g. revegetation) should occur as soon as possible after grading. In colder climates, a mulch cover is needed to stabilize the soil during the winter months when grass does not grow or grows poorly.65xxxxxxxxxxxxxFor guidelines on soil stabilization see USEPA (2005), USEPA (2003) as well as FIEC (2002), Sappi (2004) and FESA (1999) for forestry areas specifically. For crop-farming see SuSFarMS (2008), DOW (2006) and Devlin et al. (2002) and for mining see DWA (2008f, 2008e, 2008c, 2008b, 2008a, 2007a, 2006b and 2006a).
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Soil stabilizationSlope stabilisation involves covering the exposed slope with stockpiled topsoil, then using mats, pegs, mesh and grass to stabilise the topsoil and allow revegetation, which should be facilitated using indigenous plants.27, 35xxxxxxxxxxxxxxxxxxxFor guidelines on slope stabilization and rehabilitation see USEPA (2005) as well as FIEC (2002), Sappi (2004) and FESA (1999) for forestry areas specifically. For crop-farming see SuSFarMS (2008), DOW (2006) and Devlin et al. (2002) and for mining see DWA (2008f, 2008e, 2008c, 2008b, 2008a, 2007a, 2006b and 2006a).
81
Site clearingWhere impermeable layers are breached they should be re-instated to prevent contamination and loss of groundwater.32xxxxxxxxxxxxxxx
82
Stockpile managementUnprotected stockpiles are very prone to erosion and therefore must be protected. Small stockpiles can be covered with a tarp to prevent erosion. Large stockpiles should be stabilized by erosion blankets, seeding, and/or mulching.65xxxxxxxxxxxFor guidelines on the protection and stabilization of stockpiles see USEPA (2005). For forestry see FIEC (2002), Sappi (2004) and FESA (1999). For crop-farming see SuSFarMS (2008), DOW (2006) and Devlin et al. (2002). For construction sites see USEPA (2006). For mining see DWA (2008f, 2008e, 2008c, 2008b, 2008a, 2007a, 2006b and 2006a).
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Residue managementUse of a chopper-roller to mulch the slash, which is then spread evenly over the compartment, is effective for controlling erosion, retaining soil moisture and increasing nutrient release (instead of fertiliser use).35xxFor guidelines on mulching slash see FIEC (2002), Sappi (2004) and FESA (1999) for forestry. For crop-farming see SuSFarMS (2008), DOW (2006) and Devlin et al. (2002).
84
Residue managementMulch tilling is the practice of tilling crop residue from the previous harvest into the soil as mulch by using non-inversion tillage methods such as chiselling and disk harrowing to partially incorporate organic material left on the soil surface. This protects the soil against erosion and adds nutrients to the soil so can be used instead of fertiliser.66xxFor guidelines on mulching tilling see USEPA (2003) as well as FIEC (2002), Sappi (2004) and FESA (1999) for forestry . For crop-farming see SuSFarMS (2008), DOW (2006) and Devlin et al. (2002).
85
Soil stabilizationMulching is an erosion control practice that uses materials such as grass, hay, wood chips, wood fibres, straw, or gravel to stabilize exposed or recently planted soil surfaces. In addition to stabilizing soils, mulching can reduce stormwater velocity, improve the infiltration of runoff and add nutrients to the soil (instead as using fertilizer). Specific types of mulching also mentioned are hydro-mulching and straw mulching (below).64xxxxxxxxxxxxxFor specific guidelines on mulching see USEPA (2006), USEPA (2003) as well as FIEC (2002), Sappi (2004) and FESA (1999) for forestry. For crop-farming see SuSFarMS (2008), DOW (2006) and Devlin et al. (2002).Mulching is often used in areas where vegetation cannot be established.64
86
Soil stabilizationHydro-mulching is a process by which wood fibre mulch, processed grass, hay or straw mulch is applied with a tacking agent in a slurry with water to provide temporary stabilization of bare soils. This mulching method provides uniform, economical slope protection. It may be combined with hydroseeding as a revegetation method.62, 66xxxxxxxxxxxxxFor more on hydromulching see USEPA (2003). For guidelines on mulching see USEPA (2006).
87
Soil stabilizationStraw mulch is applied on slopes or exposed areas to hold the soil and prevent loss of grass seed. Straw mulch provides erosion control and moisture conservation, and it prevents soil crusting. 66xxxxxxxxxxxxxFor more on straw mulching see USEPA (2003). For guidelines on mulching see USEPA (2006).
88
Soil stabilizationStraw crimping is the practice of using a crimping disc, such as a sheepfoot roller, to place straw mulch on the ground. Crimping anchors the straw to the ground to hold it in place more securely.66xxxxxx
89
Soil stabilizationThe following measures can be used to stabilize soils for site preparation and construction: hydromulch (see above), straw (placed evenly on slope), crimping (rolling the placed straw with a sheep-foot roller), seeding, fertiliser, transplanting and net (jute netting pinned onto the slope).64, 66xxxxxxxxxxxxSee USEPA (2006) for guidelines on as well as other soil stabilisation measures and USEPA (2003) for more on soils stabilization.These are very effective (and mostly intended) for land preparation and during construction (especially of roads).66
90
Soil stabilizationSoil roughening is a temporary erosion control practice that increases the relief of a bare soil surface with horizontal grooves by either stair-stepping (running parallel to the contour of the land) or using construction equipment to track the surface. Soil roughening reduces runoff velocity, increases infiltration, reduces erosion, traps sediment, and prepares the soil for seeding and planting by giving seed an opportunity to take hold and grow.32, 64xxxxxxxxxxxxxFor guidelines on soil roughening see USEPA (2006) as well as DWAF (unknown).Soil roughening is appropriate for all slopes, but works especially well on slopes greater than 3:1, on piles of excavated soil, and in areas with highly erodible soils. This technique is especially appropriate for soils that are frequently disturbed, because roughening is relatively easy.64
91
Residue managementIf sash cannot be spread evenly over the compartment then it should be placed parallel to the contour with "gates" between the slash rows (to provide access).35xx
92
Residue managementDO NOT burn slash unless absolutely necessary (e.g. for access or to reduce the risk of uncontrolled fires) and then it must not be done near the end of the rainy season.35, 60xx
93
Site clearingThe most efficient approach to control erosion is to minimise the area of land disturbed as well as the duration for which it is exposed.17, 28xxxxxxxxxxxxxxxxxxx
94
Site clearingOnce surfaces have been exposed they should immediately be protected from erosion, so limiting the source of the sediment.17, 28xxxxxxxxxxxxxxxxxxxFor descriptions of simple and practical erosion control measures consult Appendix E in DWA (2006a).
95
Residue managementAfter or during harvest the un-harvested part of the crop should be trashed (broken up) and scattered over the ground to form a 'trash blanket'. This protects it from erosion, conserves soil moisture, reduces weed growth and increases soil nutrients and crop yield.60xx
96
Sediment controlsSediment capturing involves the utilisation of structural and vegetative practices to reduce sediment loads in runoff through capture as well as settling due to the reduced velocity of the runoff.17, 28xxxxxxxxxxxxxxxxxxxFor descriptions of simple and practical traps consult Appendix E in DWA (2006a).
97
Soil stabilizationThe banks of excavated areas are highly prone to slope failure and erosion and should be protected using appropriate stabilization measures, such as retaining walls or rock gabions.22, 28, 32, 34,35, 60xxxxxxxxxxFor guidelines on stabilising pit walls see SuSFarMS (2008) for crop farming, FIEC (2002) and FESA (1999) for forestry, DWA (2006a) for small scale mining, DWA (2008b) for surface mining, DWA (2008c) for underground mining and DWA (2008d) for all mining.
98
Site clearingDuring the excavation of pits, roads, construction sites etc. the removed topsoil should be stored and appropriately protected so that it does not wash into waterbodies, causing sedimentation and nutrient loading. This is then used to backfill the area so that it can be effectively rehabilitated.22, 27, 28, 32, 34, 35, 60xxxxxxxxxxxFor guidelines on storing topsoil to backfill and rehabilitate ponds, pits, roads etc. see SuSFarMS (2008) for crop farming, FIEC (2002) and FESA (1999) for forestry, DWA (2006a) for small scale mining, DWA (2008b) for surface mining, DWA (2008c) for underground mining and DWA (2008d) for all mining.
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Site clearingTopsoil that is removed during excavation should NEVER be buried or rendered unusable in any way (such as mixing it with spoils or being compacted by machinery).17, 18, 21, 28, 32, 34, 35, 44, 60xxxxxxxxxxxFor guidelines on the appropriate storage of topsoil see SuSFarMS (2008) for crop farming, FIEC (2002) and FESA (1999) for forestry, DWA (2006a) for small scale mining, DWA (2008b) for surface mining, DWA (2008c) for underground mining and DWA (2008d) for all mining.
100
Site clearingDuring excavation soil should be excavated one layer at a time and stored in separate stockpiles so they can be returned in their natural order when the area is backfilled. This improves soil functions and improves the template for plant growth.32, 44xxxxxxxxxxx