Camperdown Game Estate
for Rob Kirby
Executive Summary In response to a request from Rob Kirby we submit the following prospective and innovation document for the game estate developments proposed by the developer. We understand that KV3 may already have completed some work on the initial project stage. In respect to KV3 we request that their work be reimbursed (if a different engineer is employed) or that they are kept on the professional team. This recommendation is made, by us, in line with our core value of respect. We enjoy a good working relationship with Rob Kirby so offer this document, freely, as a building step for your projects. Dominic Collett 26 May 2010
Regency House, 3 Douglas Crowe Dr Ballito Business Park Ballito, 4420 Tel: +27 (0) 32 9463848 Fax: +27 (0) 32 5860007 Tel (Direct): +27 (0) 82 3206256 Mobile: +27 (0) 82 3206256 Email: dominicc@ssi.co.za www.ssi-dhv.com PO Box 6340 Zimbali, 4418 South Africa
RESPE
Introduction Providing a world class estate is a team effort. From the planning and design of the living environment, opportunities exist to build relationships, to empower communities and to create a better quality of life. The spark that transforms a project into a winning project is INNOVATION. The ability to look at a problem and to see opportunities is what is needed now more than ever before. SSI Engineers and Environmental Consultants has established a culture of innovation, which has been of real benefit to “whole life thinking�. All this is embodied in our core values of
RESPECT, INNOVATION AND FREEDOM
ECT, INNOVATION AND FR
STORMWATER CONTROL AND
ATTENUATION
SSI have developed a specialised section for the planning, design and construction management of prestige residential developments. This experience has been obtained over many years and has focused on the requirements of clients determined to provide to their customers where the engineering is of the highest quality. Inherent in this process is sensitivity to the environment and the development of a low maintenance infrastructure. This is particularly important in the management of stormwater, and SSI have developed innovative ways in which the realities of high rainfall in geotechnically sensitive areas may be addressed without resorting
to hard engineering solutions, which may detract from the visual appearance of the development. La Lucia Ridge, The Gardens, Ilala Ridge and Kindlewood are all residential projects in Umhlanga. The sensitive Berea Red and windblown cohesionless sands in these areas required careful consideration. In response to this, SSI developed a stormwater master plan which provides for underground stormwater attenuation as site level through to attenuation in dams in a conservation zone which controls the stormwater outflow to pre-development levels.
Geo Step - textile soil reinforcement GEO STEP | TEXTILE SOIL REINFORCEMENT Vetiver grass clay fill Grass lined drain - no fall
600mm
Concrete lip with Y12 central reinforcement
1. roll out fabric and fill with clay
200mm
Fencing standards at 500mm intervals
Construction process
The lowest step is extended to a 2000mm length 2 . cover with fabric and secure leading edge
One of the more important aspects of stormwater control is consideration of the house construction phase, during which the site is stripped of much of its natural vegetation and the system is vulnerable to increased runoff and erosion of the valuable topsoils. The installation of the underground attenuation system prior to any construction, controls the runoff and traps the eroded soil before it leaves the site. Where the development takes place adjacent to wetlands, the attenuation system is adapted by the addition of an infiltration system to return the low flow stormwater to the ground, recharging the natural groundwater and further reducing the site runoff. Where the valley bottom becomes overstressed as a result of the development, additional measures need to be taken to ensure that the stormwater carrying capacity of the soil/ vegetation interface is not exceeded. In many instances the reaction to potential erosion is to opt for a traditional engineering solution. This can both be expensive and an overlay conservative reaction. There are interim measures which can be implemented and SSI has been at
GEO ROLL | CHECK WEIR CONSTRUCTION GeoRoll - Check Weir Construction the forefront of the development of such measures as GeoStep and GeoRoll soil reinforcement, which are economical and environmentally acceptable. With the requirements of current legislation imposing onerous requirements on developers, it is necessary to address these issues properly and competently. SSI has a reputation for doing just that and we have been professional team for many of the most successful projects in recent years.
Bond the leading edge of the fabric using "Dam Seal" bitumen emulsion
Water flow For additional protection, spray exposed fabric surfaces with bitumen emulsion (cover the bitumen with local sand while still tacky for a natural appearance)
Grass lined drain
GeoRoll to be constructed using Geo Container fabric by Kaytech. Generally 600mm in height filled with local non-erodable material
0% grade to the top of the next GeoRoll
Grass lined drain
Geo Container fabric
Fabric extended for a nominal 3 metre apron held in place with dry packed handstone
Vetiver grass
Original Ground
Tapered end of GeoRoll to be stitched and buried - Alternatively "Dam Seal" may be used.
Final Profile
Geo Container fabric
Road Construction SSI have been in the forefront of concrete road construction as a means of controlling stormwater drainage and providing access. The use of concrete strips on flatter terrain allows for a more aesthetically soft approach as apposed to the use of conventional wide premixed road construction. Gravel roads have its place within an estate but needs to be carefully identified in terms of functionality and appearance. Concrete strip construction has limitations in terms of application on steep grades where a more substantial construction is required to combat soil erosion. The use of concrete on steep grades allows for the stormwater runoff to be controlled within the road surface and discharged at low points and intervals along the drainage line.
The road geometry is critical to the successful control of stormwater drainage. The use of pipes and kerbs can be eliminated if the natural slope of the terrain is followed. We have also had very good results using permeable paving blocks. This construction offers the opportunity to attenuate stormwater runoff to pre-development flows by collecting the a volume of water within the road layerworks structure. On a recent project this eliminated all conventional stormwater drainage. This system allows for the reloading of the aquifers and offers a environmentally sensitive approach to hardened areas.
SANITATION
ELEcTRIcITY
SSI have one of the largest Research and Development budgets in the consulting engineer field. This research and development is mainly around Water and Waste Water Treatment. We have patented a number of processes. A sanitation solution is dependent on a number of criteria that need to be identified before proposing a specific solution.
SSI have completed a number of large scale solar panel and hot water installations. This technology can be designed to meet the estate’s requirements.
Water reuse is our core sanitation approach which has been successfully implemented throughout the country in answer to our limited water resource.
Conclusion
Each project has unique features for consideration, and requires new specific innovation ideas. We look forward in assisting your team on this exciting project.
Acknowledgments
Photos | Tony Smith
Design and Productions | Estate Press Publications
Regency House, 3 Douglas Crowe Dr Ballito Business Park Ballito, 4420 Tel: +27 (0) 32 9463848 www.ssi-dhv.com