PROPOSED CONSTRUCTION OF THE DASBOSCHFONTEIN OFF-CHANNEL DAM, FARM 16/2, MOORREESBURG Draft Environmental Impact Assessment Report: Executive Summary ~ March 2009
[Acting as agent on behalf of Africon (Pty) Ltd]
The Dasbosch Familie Trust is proposing to construct a new off-channel storage dam on the farm Dasboschfontein 16, portion 2. The farm is located approximately 13km south of the town of Porterville, and is located within the Berg River Local Municipality (refer to Figure 1.1 attached). The Dasbosch Familie Trust is a producer and exporter of fresh fruit and vegetables for both domestic and international markets. The farm currently consists of 9 hectares of table grapes, 70 hectares of vegetables and 82 hectares of citrus orchards. The Dasbosch Family Trust is in the process of expanding its farming activities, to include an additional 15 hectares of table grapes and 60 hectares of citrus orchards within its existing development. The farm currently obtains its water from the Vier en Twintig irrigation scheme, and intends to store its winter allocation for use in the summer months, to facilitate the expansion. Ninham Shand Consulting Services was appointed by Dasbosch Familie Trust to undertake an Environmental Impact Assessment (EIA) process, in terms of the National Environmental Management Act (No. 107 of 1998), for the activities relating to the proposed farm dam and associated infrastructure. The Scoping Phase of this EIA process was completed and a Final Scoping Report (FSR) was submitted to the responsible authority, namely the Department of Environmental Affairs and Development Planning (D: EA&DP)), in August 2008. The FSR and associated Plan of Study (PoS) were approved in December 2008, allowing the Dasbosch Familie Trust to proceed to the next phase of the EIA process; namely the Environmental Impact Assessment Phase. A draft Environmental Impact Assessment (EIA) Report, of which this document is a summary, has been released for public comment on 16 March 2009.
The proposed dam would facilitate the storage of the farm‟s winter allocation, which equates to some 400 000 m3 of water. The proposed development located on the northern portion of the farm, would entail the construction of a new earthfill embankment dam with a maximum wall height of some 11 metres, a total crest length of 740 metres (which would include the length of the spillway), and have a maximum water depth of 9.5 metres. The dam would consist of a grass lined open channel spillway along the left flank of the dam wall. The anticipated inundation area would be some 8 hectares of agricultural land. As mentioned above, the water would be provided from the Vier en Twintig river canal system, located along the eastern section of the proposed dam, via an existing earth diversion channel. A
sluice gate would be installed on the canal to control the diversion of water to the dam during the winter months.
It is a requirement of the EIA process that due consideration is given to reasonable alternatives, although not all alternatives need to be investigated at the same level of detail. The Final Scoping Report (FSR) identified and screened the activity, location, process and layout alternatives with respect to the construction and operation of the proposed farm dam. The following sections summarise the outcome of the Scoping Phase and hence describe the proposed project alternatives. Activity Alternative: The main function of the proposed dam is to ensure adequate water is available during the summer months, to supplement the expanded agricultural activity at the Dasboschfontein Farm. In order to utilise the 400 000m3 of water that is legally available for storage during the winter months, the construction of the Dasboschfontein dam is proposed. Consequently, the only activity alternative being considered is the construction of a 400 000m3 off channel dam located on the Dasboschfontein farm. The „no-go‟ alternative is the alternative of not utilising the full winter allocation given to the Dasbosch Familie Trust by not constructing the proposed dam. The “no-go” option was considered during the EIA. It was however not assessed separately, but rather it was considered as the status quo against which the proposed development was compared. Layout alternatives: The central point of the Dasbosch Farm irrigation system is located at the Verdeel Dam, located to the south of the proposed dam site. As such, the water stored within the proposed dam would need to be transferred to the Verdeel Dam in order to effectively distribute the water to other parts of the farm. In terms of a layout alternative, there were two options assessed for the transfer of water from the preferred dam to the existing Verdeel Dam. The intention was to either utilise an existing earth diversion channel that runs from the proposed dam site to the Verdeel Dam. This is currently utilised to facilitate the transfer of water from the two seasonal tributaries to the Verdeel Dam. The alternative option involved the installation of a 200 mm HDPE outlet pipeline to transfer the water between dams. The proposed pipeline would be buried, and laid within the existing servitude of the earth diversion channel.
The Scoping Phase of this process identified several operation and construction phase impacts that were proposed to be assessed in the EIA Phase, which are as follows: Operation Phase Impacts: Impact on terrestrial flora and fauna; Impact on the aquatic flora and fauna; Impact of founding conditions on site suitability; Visual impacts; Heritage impacts
Construction Phase Impact Vehicular traffic impacts Visual impacts; Impact on ambient noise levels in the area; Dust Impacts In order to comply with the requirements Section 38 (8) of the National Heritage Resources Act (No 25 of 1999), a Phase One Heritage Impact Assessment was conducted.
Public Participation Process
The public participation process forms an integral component of the EIA process. The public participation process to date has involved the following aspects: Placing a notice in the local newspaper, Swartlander, on 30 April 2008 advertising the commencement of the EIA process. The advertisement served to advertise the initiation of the study and invited Interested and Affected Parties (I&APs) to register and provide comment; and Distributing a letter and Background Information Document to identified interested and affected parties (I&APs), inviting them to raise any issues or concerns and to indicate any other potential I&APs that should be contacted, The lodging of the draft Scoping Report (DSR) in the Porterville public library, the Porterville Municipal Office and on the Ninham Shand website (www.ninhamshand.co.za) for a 30 day comment period. Conducting a site visit/focus group meeting to discuss the findings of the DSR. Distributing a letter informing all registered I&AP‟s of the submission of the Final Scoping Report (FSR).
The next stage of the public participation process involves the lodging of the draft EIA Report in the Porterville public library, Porterville municipal office and on the Ninham Shand Website, for public comment. Letters were sent to all registered I&APs on 16 March 2009, informing them of the availability of the report for their review and opportunity to comment.
Methodology and Assessment
The methodology applied during this EIA is broadly consistent with that described in DEAT‟s Guideline Document on the EIA Regulations (1998). The methodology was outlined in the Plan of Study for EIA. Using a tabulated rating system, each impact is described according to its extent (spatial scale), magnitude (size or degree scale) and duration (time scale). These criteria are used to ascertain the significance of the impact, firstly in the case of no mitigation and then with the most effective mitigation measures in place. Once the significance of an impact has been determined, the probability of this impact occurring as well as the confidence in the assessment of the impact is determined. Lastly, the reversibility of the impact is estimated. Challenges faced during the application of the methodology as described relate to the subjectivity in assigning significance to an impact. In recognising the extent of the information available at this stage of the project, the confidence in the environmental assessment undertaken is regarded as acceptable for informed environmental decision making.
Conclusion and Recommendations
Based on the outcome of the EIA Phase of the proposed project, it is believed that the draft EIA Report provides a relatively comprehensive investigation and assessment of the environmental issues raised during the Scoping Phase by I&APs, commenting authorities, Dasbosch Familie Trust and the EIA project team.
Operation Phase Impacts: The most significant operational phase impacts of the proposed farm dam and its associated infrastructure (i.e. layout alternatives) on the biophysical and social environment, without mitigation, include the following: Impact on aquatic fauna and flora on the two seasonal tributaries; Heritage impacts of the proposed dam and associated infrastructure; and Visual impact of the proposed dam.
It must be noted in the context of this proposed activity, the highest negative impact will be of a Low to very low (-ve) significance (heritage impact). Appropriate mitigation measures can effectively reduce the significance of the associated impacts even further. Construction Phase Impacts: None of the construction phase impacts were deemed to have a highly significant impact on the environment, given their relatively short duration and localised extent. The following potential impacts have been identified as relevant to the construction of this project: Vehicular traffic impacts Visual impacts; Impact on ambient noise levels in the area; Dust Impacts
However, many of the construction phase impacts are of low significance and a suite of mitigation interventions can be implemented to avoid and minimise impacts on the biophysical and social environment. A Construction Environmental Management Plan (EMP) and associated Specification Data have been developed to guide the construction phase of the proposed project. The implementation of the EMP would minimise possible negative impacts on construction and assigns responsibility for environmental controls. Recommendations With reference to the operational impacts described above, it can be noted that their significance levels could generally be reduced by implementing the identified mitigatory measures as highlighted in Chapter 5 of the EIA Report. Assuming that the identified suite of mitigatory measures is implemented, the following describes the various project alternatives in terms of their biophysical and socio-economic impact: Activity alternative: In reviewing the potential impacts associated with the proposed dam, it is evident that the development may have an impact on the surrounding social and biophysical environment. However, the implementation of the suggested mitigation measures will reduce the significance of many of the impacts, thereby not resulting in the proposed activity having unacceptably high impacts. Layout Alternative:
Based on the assessment of the layout alternatives, it has become evident that the utilisation of the existing earth diversion channel will result in similarly limited environmental impacts, as compared to the proposed installation of the 200mm HDPE buried pipeline. As such, it is recommended that both alternatives be authorised and that the technical and financial considerations be used to determine which alternative to pursue.
The next stage of this EIA process involves lodging the draft EIA Report for public review and comment. The opportunities for public involvement are as follows: Commenting on the Draft EIA Report, which has been lodged at the Porterville public library, the Porterville local municipal office, as well as on the Ninham Shand (www.ninhamshand.co.za) website; The public will have until 20 April 2009 to submit written comment on the Draft EIA Report to Ninham Shand; and All registered I&APs have been notified of the availability of the draft EIA Report by means of a letter which includes a copy of this draft EIA Report Executive Summary.
Once the final EIA Report has been completed and all I&APs comments have been incorporated into the report, where appropriate, the report will be presented to the Dasbosch Familie Trust for their comment and review. The final EIA Report will be submitted to D: EA&DP for review and decision making. Their decision will be documented in an Environmental Authorisation and registered I&APs will be informed accordingly of their opportunity to appeal the decision to the Minister of Environmental Affairs and Development Planning in terms of the National Environmental Management Act.