National Road 3: Keeversfontein to Warden (De Beers Pass Section)
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National Road 3: De Beers Pass Section Final Environmental Impact Assessment Report February 2016 NATIONAL ROAD 3: KEEVERSFONTEIN TO WARDEN (DE BEERS PASS SECTION) CHAPTER 6: THE RECEIVING ENVIRONMENT 6. THE RECEIVING ENVIRONMENT 6.1 REGIONAL LOCATION The section of the N3 under consideration stretches from Keeversfontein (Tugela Toll Plaza) in KwaZulu-Natal to the town of Warden in the Free State. The study area is bounded in the west by the existing N3 and in the east by the proposed De Beers Pass Route (Figure 6-1). The District Municipalities through which the route alternatives pass are: Free State: Thabo Mofutsanyane District Municipality (Figure 6-2); and KwaZulu-Natal: Uthukela District Municipality (Figure 6-3). Four Local Municipalities, namely Emnambithi, Pumelela, Okhahlamba and Maluti-a- Phofung are affected. 6.2 CLIMATE This climatic information is gleaned from the Air Quality and Climate Specialist Report undertaken by Airshed (Volume 2: Appendix D). The following South African Weather Services (SAWS) and Agricultural Research Council (ARC) weather stations were used to provide meteorological data for the study area: Van Reenen (SAWS identification number 0333682A9); Warden Heritage (SAWS identification number 0369118A3); and Harrismith Blokhuis (ARC identification number 30686). Although some of these stations have statistical summaries dating back to the 1920s, the use of automatic weather stations was only initiated during 2006. This data includes hourly average wind speeds, wind directions, ambient air temperature, relative humidity, barometric pressure and rainfall. Cave Klapwijk and Associates 6-1 National Road 3: De Beers Pass Section Final Environmental Impact Assessment Report February 2016 Figure 6-1: Regional Location of the Study Area Cave Klapwijk and Associates 6-2 National Road 3: De Beers Pass Section Final Environmental Impact Assessment Report February 2016 Figure 6-2: Thabo Mofutsanyane District Municipality 6.2.1 Ambient Air Temperature Table 6-1 shows the monthly variation of historical dry bulb temperature measurements made at Harrismith. This data was taken from the SAWS summary of 1932-1940 (WB40, 1984). The average daily minimum/maximum is the sum of the minimums and maximums for every day in the relevant month divided by the number of records. The average monthly minimum/maximum is the minimum/maximum recorded for each of the relevant months divided by the number of records. The period minimum/maximum is the lowest/highest temperature recorded for the entire reporting period. The very low temperatures are a clear indication of the extremely cold conditions that can be experienced in the study area. Cave Klapwijk and Associates 6-3 National Road 3: De Beers Pass Section Final Environmental Impact Assessment Report February 2016 Figure 6-3: Uthukela District Municipality Table 6-1: Historical monthly average temperature statistics for Harrismith (WB40, 1984) WB40 (1932-1940) WB40 (1932 -1940) Average for the Period Month Average Monthly Average Daily (1932 – 1940) Min (°C) Max (°C) Min (°C) Max (°C) Min (°C) Max (°C) Jan 3.9 34.7 6.5 31.2 12.6 25.9 Feb 3.3 32.2 6.7 29.6 12.1 24.9 Mar 3.9 31.7 4.8 28.8 10.1 24.4 Apr -5.6 30 -1.3 27.3 5.7 22.1 May -10 27.2 -5.4 24.4 1.1 19 Cave Klapwijk and Associates 6-4 National Road 3: De Beers Pass SectionDraft Environmental Impact Assessment Report February 2016 WB40 (1932 -1940) Average for the Period Month Average Monthly Average Daily (1932 – 1940) Min (°C) Max (°C) Min (°C) Max (°C) Min (°C) Max (°C) Jun -11.7 23.3 -7.9 20.6 -2.8 16.3 Jul -12.8 23.3 -8.4 20.2 -2.3 15.9 Aug -11.7 26.1 -6.9 24.2 0.1 18.5 Sep -6.7 30 -2.9 28.6 3.8 21.9 Oct -1.1 33.3 1.8 30.5 9 23.8 Nov -2.2 32.8 3 30.6 9.7 23.9 Dec 3.9 32.8 6.1 31.1 11.6 25.1 Table 6-2 is a comparative summary of more recent temperature data for Harrismith and Van Reenen from ARC (2000 – 2004 and 2007 - 2010). Table 6-2: Historical monthly average temperature statistics for Van Reenen ARC (2000- 2004) and Harrismith ARC (2007-2010) ARC (2000-2004) ARC (2007-2010) Van Reenen No 30274 Harrismith No 30686 Month Average Daily Average Monthly Average Daily Min (°C) Max (°C) Min (°C) Max (°C) Avg Min (°C) Max (°C) Jan 11.8 25.1 8.9 30.5 19.5 13.6 25.4 Feb 12.3 25.2 9.1 31.3 19.3 13.5 25.1 Mar 11.4 24.1 0 30.1 18.3 11.6 24.4 Apr 7.5 23.3 -1.9 26.3 14.8 8.1 21.5 May 3.1 20.3 -5.8 26.0 12.1 4.9 19.2 Jun -0.5 17.4 -8.5 25.8 8.9 2.0 15.8 Jul -1.2 14.4 -4.1 22.8 9.2 1.6 16.8 Aug 2.1 21.5 -4.3 27.9 11.4 3.9 18.9 Sep 5.2 21.2 -1.3 30.2 15.4 7.3 23.3 Oct 9.4 24.0 4.5 31.1 16.5 9.9 23.0 Nov 9.8 24.9 6.9 30.6 17.9 11.5 24.2 Dec 12.3 26.6 6.7 30.0 19.1 12.9 25.3 Data was obtained from ARC (2000-2004), an online UK climate database (2000-2008), and measured SAWS hourly data (2009-2010). Average monthly and average daily temperatures from the ARC station (2000-2004) are given in Table 6-2, with SAWS (2009-2010) summaries in Table 6-3. Table 6-3: Monthly average temperature statistics for Van Reenen (Weather Online, SAWS) Weather online (2000-2008) SAWS (2009-2010) Van Reenen Harrismith Month Avg Daily Avg Monthly Avg Daily Min (°C) Max (°C) Avg (°C) Min (°C) Max (°C) Avg (°C) Min (°C) Max (°C) Jan 13.9 24.5 19.1 10.9 29.8 18.2 13.0 22.4 Feb 13.4 24.1 18.7 9.1 31.2 18.3 10.6 23.0 Mar 11.7 22.8 17.2 8.2 28 17.1 11.4 21.6 Apr 8.8 21.4 15.1 1.5 26.9 14.2 6.2 18.8 May 4 19.4 11.7 -1.3 29.5 11.5 6.1 16.1 Jun 1.7 16.8 9.2 -7.2 26.4 8.5 0.4 14.8 Jul 1.2 17 9 -8.5 20.8 7.4 0.0 13.3 Aug 4.7 19.5 12.2 -7.2 26.8 10.4 2.7 17.4 Sep 7.5 21.9 14.8 1.8 29.6 15.0 5.9 21.2 Oct 10.6 22.6 16.7 4.6 31 15.4 7.3 22.4 Nov 12.4 23.9 18.1 4.3 29.8 16.4 6.5 22.2 Dec 13.1 24.6 18.8 9.6 31.3 17.8 10.9 22.7 Cave Klapwijk and Associates 6-5 National Road 3: De Beers Pass SectionDraft Environmental Impact Assessment Report February 2016 Table 6-4 shows the average monthly and average daily temperatures for Warden (measured hourly SAWS data for 2009-2010). Table 6-4: Monthly Average temperature statistics for Warden (SAWS) SAWS (2009 – 2010) Avg Monthly Avg Daily Month Min (°C) Max (°C) Avg (°C) Min (°C) Max (°C) Jan 12.7 30.8 19.7 15.1 23.1 Feb 10.4 31.5 19.3 12.8 23.9 Mar 8.3 29.8 17.8 14.4 21.2 Apr 1.6 27.9 14.9 7.9 19.4 May -0.3 23.4 12.0 6.7 15.0 Jun -7.2 25 8.8 1.1 15.4 Jul -6.3 21.2 7.9 2.1 12.9 Aug -3.7 26.4 10.9 3.1 17.3 Sep 2.8 29 15.9 10.1 20.2 Oct 3.6 30.5 16.8 7.6 22.7 Nov 6.5 30.7 17.3 8.9 22.4 Dec 9.9 31.5 18.8 13.4 22.8 6.2.2 Wind Speed and Direction Hourly average wind speed and direction data was obtained from the automatic weather stations operated by the SAWS at Van Reenen and Warden. This data was analysed, and summarised as wind roses in Figure 6-4 and Figure 6-5. These wind roses comprise 16 spokes, which represent the directions from which winds blew during the period. The colours reflect the different categories of wind speeds; the grey area in Figure 6-4 and Figure 6-5, for example, represents winds ranging between 1 and 2 m/s. The dotted circles provide information regarding the frequency of wind occurrence (speed and direction categories). For the current wind roses, each dotted circle represents a 5 % frequency of occurrence. The value given in the centre of the circle describes the frequency with which calms occurred, i.e. periods during which the wind speed was below 1 m/s. “Daytime”, “night-time” and “period” wind roses represent the wind conditions during the hours 06h00 to 18h00, 18h00 to 06h00 and 01h00 to 24h00, respectively. Cave Klapwijk and Associates 6-6 National Road 3: De Beers Pass Section Final Environmental Impact Assessment Report February 2016 Figure 6-4: Wind Roses for Van Reenen Cave Klapwijk and Associates 6-7 National Road 3: De Beers Pass SectionDraft Environmental Impact Assessment Report February 2016 Figure 6-5: Wind Roses for Warden The only source of wind data for Harrismith (Figure 6-6) was from ARC.