Appendix 2: Rainfall Analysis
All data used in this analysis were extracted from the Bureau of Meteorology Climate Database.
Regional rainfall analysis in the Australian Capital Region is complicated by several factors including:
- Intermittent coverage at specific locations. While the Bureau of Meteorology has a considerable number of volunteer rainfall observers, many of the sites have gaps within the records. Although there are several excellent long-term rainfall sites available and still open in the region, there are many more that have records of varying length that do overlap. If one site closed, the Bureau of Meteorology attempted to open another site close by. Averaging between several nearby sites with data highly correlated with that at the chosen site can be used as a simple method of filling gaps in the record.
- Missing data. While rainfall does vary both spatially and temporally in the short term, analysis of data from nearby sites indicates that in cases where there are overlapping records for a long period of time there are frequently high correlations on a month by month basis between these sites. This means that linear regression can be used to calculate values to fill the missing months in these records.
Selection of Sites
The main rainfall site chosen to represent the location within each Local Government Area (LGA) was that site that was still open and with the longest continuous record. Gaps in the data were then filled using linear regression with data for surrounding sites with overlapping records:
- Comparisons were made with sites with suitable data that were as close as possible both for the period 2004-2008 and for the period pre-2004.
- Provided the correlation values were over 0.8, linear regression formulae obtained from these comparisons were then used to calculate the missing values for the site chosen to be the main site for the region.
- Where a number of sites needed to be used to fill the gaps, such as at Goulburn, and the correlation values were less than 0.8, then an average of the values calculated for the main site from each alternative site was used.
Data for the LGAs fall into 4 categories
1. The site has a full record with no gaps. The sites in this category are:
Queanbeyan
Tumbarumba
Moruya Heads
Taralga
2. The site has a few individual months missing in the record. The sites in this category are:
Adaminaby*
Tumut
Bombala (Bukalong)
Narooma (Bodalla)
Young (Wombat)
Crookwell
Braidwood (Wallace St)
3. The site has a series of months/years missing. The sites in this category are:
Goulburn (Kippilaw)
Eden (Caravan Park)
Bega (Newton Rd)
Cootamundra (Landgrove)
Boorowa
Harden (Murrumburrah)
Bungendore (Gidleigh)
Cabramurra*
4. The comparison with another nearby site is sufficient to develop a time series that precedes the date when the site was opened. The sites in this category are:
Cooma (Kiaora)
Yass
Gundagai (Mt. Horeb)
* The derived monthly rainfall data developed for Adaminaby and Cabramurra used in this analysis can only be treated as indicative, as there was a lack of good quality data from nearby sites for comparison. Although an Automatic Weather Station (AWS) has been installed at Cabramurra, the correlation with data from the manual site before it was closed is not as high as would be expected given the proximity of the new to the old site. Relationships with data from sites near to Cabramurra are also affected by the differences in altitude in the region.
The selected sites and the secondary sites used to fill data gaps for this analysis are listed below, with the main site in red in each case.
| Adaminaby | Approx Distance | Lat | Long | Elevation | R2 valuewith 72100 |
|---|---|---|---|---|---|
| Alpine Tourist Park 1886-2008 071000 | 0.4 km | 36.00S | 148.77E | 1015 m | |
| Eucumbene Trout Farm 1973-2008 071043 | 30.7 km | 36.27S | 148.72E | 1050 m | 0.68420.7548 (post 2004) |
| Buckenderra 2003-2008 071026 | 20.2 km | 36.18S | 148.76E | 1198 m | 0.7742 |
| Bega | Approx Distance | Lat | Long | Elevation | R2 valuewith 69002 |
|---|---|---|---|---|---|
| Bega (Newton Rd) 1879-2008 069002 | 5.6 km | 36.69S | 149.84E | 50 m | |
| Bega AWS 1992-2008 069139 | 7 km | 36.67S | 149.82E | 41 m | 0.8813 0.9827 (Post 2004) |
| Candelo PO 1887-2008 069013 | 21 km | 36.77S | 149.7E | 109 m | 0.8784 |
| Bombala | Approx Distance | Lat | Long | Elevation | R2 valuewith 70009 |
|---|---|---|---|---|---|
| Bukalong 1857-2008070009 | 14 km | 36.8S | 149.2E | 785 m | |
| Bombala (Therry St) 1885-2008 070005 | 1.2 km | 36.91S | 149.24E | 705 m | |
| Bombala AWS 1994-2008 070328 | 9 km | 37.00S | 149.23E | 761 m | 0.8769 0.8412 (Post 2004) |
| Boorowa | Approx Distance | Lat | Long | Elevation | R2 valuewith 70220 |
|---|---|---|---|---|---|
| Boorowa PO 1882-2008 070220 | 0.4 km | 34.44S | 148.72E | 488 m | |
| Murringo 1968-2008 073109 | 16 km | 34.43S | 148.54E | 530 m | 0.8675 |
| Braidwood | Approx Distance | Lat | Long | Elevation | R2 valuewith 69010 |
|---|---|---|---|---|---|
| Braidwood (Wallace St) 1887-2008 069010 | 0.2 km | 34.45S | 149.8E | 643 m | |
| Braidwood Racecourse 1985-2008 069132 | 3.2 km | 35.43S | 149.78E | 665 m | 0.9297 |
| Bungendore | Approx Distance | Lat | Long | Elevation | R2 valuewith 70035 |
|---|---|---|---|---|---|
| Bungendore (Gidleigh) 1886-2008 070035 | 7 km | 35.31S | 149.47E | 725 m | |
| Bungendore PO 1890-2008 070011 | 35.25S | 149.44E | 698 m | 0.9077 |
| Cabramurra | Approx Distance | Lat | Long | Elevation | R2 valuewith 72091 |
|---|---|---|---|---|---|
| Cabramurra 1955-1999 072091 | 12.5 km | 35.94S | 148.38E | 1475 m | |
| Cabramurra AWS 1996-2008 072161 | 12.9 km | 35.94S | 148.38E | 1482 m | 0.5133 |
| Tooma 1997-2008 070028 | 35.9 km | 35.9S | 148.18S | 585 m | 0.6836 |
| Cooma | Approx Distance | Lat | Long | Elevation | R2 valuewith 70054 |
|---|---|---|---|---|---|
| Cooma (Kiaora) 1904-2008 070054 | 6.2 km | 36.2S | 149.06E | 870 m | |
| Cooma Visitors C 1973-2008 070278 | 0.4 km | 36.23S | 149.12E | 778 m | 0.9257 |
| Cooma(Lambie St) 1858-1982 070023 | 0.5 km | 36.23S | 149.12E | 812 m | 0.899 |
| Cootamundra | Approx Distance | Lat | Long | Elevation | R2 valuewith 73022 |
|---|---|---|---|---|---|
| Landgrove 1891-2008 073022 | 11.9 km | 34.65S | 148.16E | 460 m | |
| Cootamundra PO 1889-1996 073009 | 1.1 km | 34.64S | 148.02E | 318 m | 0.8918 |
| Cootamundra A/P 1995-2008 073142 | 2.3 km | 34.63S | 148.04E | 335 m | 0.8824 0.8884 (post 2004) |
| Crookwell | Approx Distance | Lat | Long | Elevation | R2 valuewith 70025 |
|---|---|---|---|---|---|
| Crookwell PO 1883-2008 070025 | 0.3 km | 34.46S | 149.47E | 887 m | |
| Crookwell(HolbrowSt) 1997-2008 070225 | 1 km | 34.46S | 149.46E | 895 m | 0.9127 0.9611 (Post 2004) |
| Gundowringa 1945-2008 070069 | 13 km | 34.54S | 149.57E | 838 m | 0.82040.8572 (Post 2004) |
| Eden | Approx Distance | Lat | Long | Elevation | R2 valuewith 69015 |
|---|---|---|---|---|---|
| Eden Caravan Park 1870-2008 069015 | 1.6 km | 37.06S | 149.91E | 9 m | |
| Pambula 1909-2008 069024 | 16 km | 36.93S | 149.87E | 10 m | 0.8596 0.9459 (post 2004) |
| Candelo PO 1887-2008 069013 | 38 km | 36.77S | 149.7E | 109 m | 0.7157 |
| Wyndham PO 1890-2008 069066 | 27 km | 36.93S | 149.65E | 300 m | 0.7289 |
| Goulburn | Approx Distance | Lat | Long | Elevation | R2 valuewith 70055 |
|---|---|---|---|---|---|
| Kippilaw 1886-2008 070055 | 12.3 km | 34.75S | 149.6E | 647 m | |
| Springfield 1930-2008 070077 | 17.8 km | 34.9S | 149.67E | 665 m | 0.8162 0.8803 (post 2004) |
| Hillwood 1960-2008 070147 | 21 km | 34.56S | 149.74E | 740 m | 0.80010.7802 (post 2004) |
| Pomery 1901-2008 070071 | 23 km | 34.65S | 149.5E | 685 m | 0.8009 0.8662 (post 2004) |
| Gundagai | Approx Distance | Lat | Long | Elevation | R2 valuewith 72154 |
|---|---|---|---|---|---|
| Mt Horeb (Marathon) 1926-2008 072154 | 17 km | 35.22S | 148.03E | 285 m | |
| Gundagai 1892-1971 073015 | 35.07S | 148.10E | 216 m | 0.887 |
| Harden | Approx Distance | Lat | Long | Elevation | R2 valuewith 73029 |
|---|---|---|---|---|---|
| Murrumburrah Old PO 1884-2008 073029 | 2 km | 34.55S | 148.35E | 370 m | |
| Harden 1892-2008073016 | 34.56S | 148.37E | 430 m | 0.9353 | |
| Murringo 1968-2008 073109 | 21 km | 36.77S | 149.7E | 109 m | 0.7997 |
| Moruya | Approx Distance | Lat | Long | Elevation |
|---|---|---|---|---|
| Moruya Heads 069018 1875-2008 | 7 km | 35.91S | 150.15E | 17 m |
| Narooma | Approx Distance | Lat | Long | Elevation | R2 valuewith 69036 |
|---|---|---|---|---|---|
| Bodalla PO 1876-2008 069036 | 36.09S | 150.5E | 42 m | ||
| Narooma 1910-2008 069022 | 14.6 km | 36.21S | 150.14S | 25 m | 0.8179 0.8789 (post 2004) |
| Moruya Heads 1876-2008 069018 | 21 km | 35.91S | 150.15E | 109 m | 0.8784 |
| Queanbeyan | Approx Distance | Lat | Long | Elevation |
|---|---|---|---|---|
| Queanbeyan B C 1871-2008 070072 | 0.6 km | 35.36S | 149.23E | 580 m |
| Taralga | Approx Distance | Lat | Long | Elevation |
|---|---|---|---|---|
| Taralga PO 070080 1882-2008 | 0.2 km | 34.4S | 149.82E | 845 m |
| Tumbarumba | Approx Distance | Lat | Long | Elevation |
|---|---|---|---|---|
| Tumbarumba P.O 072043 1882-2008 | 1.4 km | 35.78S | 148.01E | 645 m |
| Tumut | Approx Distance | Lat | Long | Elevation | R2 valuewith 72044 |
|---|---|---|---|---|---|
| Tumut (Wattle Cres) 1886-2008 072044 | 35.32S | 148.23E | 300 m | ||
| Blowering Dam 1955-2008 072056 | 10 km | 35.39S | 148.26 | 308 m | 0.9058 0.8507 (post 2004) |
| Yass | Approx Distance | Lat | Long | Elevation | R2 valuewith 70091 |
|---|---|---|---|---|---|
| Yass (Linton Hostel) 1898-2008 070091 | 1.2 km | 34.83S | 148.91 | 520 m | |
| Yass 1877-1913 070108 | 2.1 km | 34.85S | 148.9E | na | 0.9811 |
| Derringullen 1898-2006 070028 | 11 km | 34.74S | 148.89S | 595 m | 0.887 |
| Young | Approx Distance | Lat | Long | Elevation | R2 valuewith 73041 |
|---|---|---|---|---|---|
| Wombat 1888-2008 073041 | 15 km | 34.41S | 148.18E | 503 m | |
| Young Airport AWS1994-2008 073138 | 9 km | 34.25S | 148.25E | 380 m | 0.8677 0.906 (post 2004) |
