River and stream water quality and ecology - Greater Wellington ...

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River and stream water quality and ecology in the Wellington region: State and trends It should also be noted that MCI and QMCI thresholds suggested by Stark and Maxted (2007) do not take into account the natural variation in macroinvertebrate community composition that can occur in response to differences in catchment altitude, geology and other geophysical characteristics. 6.1.2 Macroinvertebrate metrics Summary statistics for the four metrics calculated (MCI, QMCI, %EPT taxa and %EPT individuals) calculated for each of the 55 RSoE sites are presented in Table 6.2. Mean MCI scores across the 55 RSoE sites ranged from a minimum of 67 (Waiwhetu Stream at Wainuiomata Hill Bridge) to a maximum of 146 (Ruamahanga River at McLays). As outlined in Section 2.3, the Waiwhetu Stream site is known to be occasionally influenced by tidal backflow and taxa indicative of estuarine conditions have been recorded at this site. Because the MCI was not designed to take into account estuarine influence its application at this site may not be appropriate. The next lowest mean MCI score recorded across the 55 sites was 75.9 (Parkvale Stream at Weir). Based on mean MCI scores, 16 sites were classified as ‘excellent’, 20 sites as ‘good’, 16 sites as ‘fair’ and 3 sites as ‘poor’. All sites classed as ‘excellent’ drain upstream catchments dominated by indigenous forest. The seven sites classed as ‘poor’ or within the ‘fuzzy boundary’ of the fair/poor threshold were found in catchments dominated by pastoral or urban landcover (Figure 6.1). All but one of these sites have substrate dominated by soft sediment – the exception being Parkvale Stream at Weir which has a relatively small catchment dominated by intensive agricultural land use. Number of sites 25 20 15 10 5 0 Indigenous forest Pasture Urban Exotic forest Excellent Good Fair Poor Figure 6.1: Macroinvertebrate quality classes assigned to each of the 55 RSoE sites, grouped according to REC landcover. Quality classes are based on the application of Stark and Maxted (2007) thresholds to mean MCI scores from annual sampling in 2009, 2010 and 2011. Hatched boxes represent sites within the ±5 MCI unit ‘fuzzy boundary’ between each class (note the result from the single exotic forestry site falls on the boundary of the fair/good threshold) WGN_DOCS-#1100598-V3 PAGE 77 OF 160
River and stream water quality and ecology in the Wellington region: State and trends Table 6.2: Mean macroinvertebrate metric (MCI, QMCI, %EPT individuals and %EPT taxa) scores at the 55 RSoE sites, based on samples collected annually in 2009, 2010 and 2011. MCI quality classes (from Stark & Maxted 2007) are also indicated; blue=‘excellent’, green=‘good’, yellow=‘fair’ and red=‘poor’ Site no. Site name MCI QMCI %EPT individuals %EPT taxa RS02 Mangapouri S at Bennetts Rd 91.5 4.46 1.2 12.7 RS03 Waitohu S at Forest Pk 145.9 8.17 90.7 71.1 RS04 Waitohu S at Norfolk Cres 94 4.63 4.7 33.5 RS05 Otaki R at Pukehinau 136.9 7.43 87.8 64.2 RS06 Otaki R at Mouth 112.6 7.3 85 42.9 RS07 Mangaone S at Sims Rd Br 82.5 4.27 0.1 6.4 RS08 Ngarara S at Field Way 80.5 4.57 0.4 7 RS09 Waikanae R at Mangaone Walkway 140.9 8.06 83 64 RS10 Waikanae R at Greenaway Rd 114.9 5.81 52.1 46.3 RS11 Whareroa S at Waterfall Rd 113.9 6.23 58.6 41.7 RS12 Whareroa S at QE Park 80.8 4.5 0.4 7.8 RS13 Horokiri S at Snodgrass 113.1 5.87 65.1 51 RS14 Pauatahanui S at Elmwood Br 106.9 5.13 48 44.9 RS15 Porirua S at Glenside 97.4 4.82 37.1 34.1 RS16 Porirua S at Wall Park (Milk Depot) 88.9 3.99 21.1 24.6 RS17 Makara S at Kennels 112.1 5.12 20.1 48 RS18 Karori S at Makara Peak 89.3 3.71 27.1 20.8 RS19 Kaiwharawhara S at Ngaio Gorge 89.8 3.44 27.9 28.7 RS20 Hutt R at Te Marua Intake Site 1 137 8.39 91.63 62.6 RS21 Hutt R opp. Manor Park Golf Club 1 124.7 6.56 70.17 62.9 RS22 Hutt R at Boulcott 1 118.1 7.28 83.11 43.8 RS23 Pakuratahi R 50m d/s Farm Ck 125 7.45 80 52.4 RS24 Mangaroa R at Te Marua 117.9 6.14 64.6 46 RS25 Akatarawa R at Hutt R confl. 130.5 7.56 84.9 57.5 RS26 Whakatikei R at Riverstone 130.3 6.61 70.9 58.8 RS27 Waiwhetu S at Wainui Hill Br 67.2 4.15 0.2 5.2 RS28 Wainuiomata R at Manuka Track 135.5 7.2 71 60 RS29 Wainuiomata R u/s of White Br 101.8 4.33 45.2 38.1 RS30 Orongorongo R at Orongorongo Stn 105.8 6.44 65.7 37.6 RS31 Ruamahanga R at McLays 146 8.03 93.3 67.6 RS32 Ruamahanga R at Te Ore Ore 110.4 6.89 75.5 46.1 RS33 Ruamahanga R at Gladstone Br 103.1 7.11 78.3 38.6 RS34 Ruamahanga R at Pukio 102.1 7.44 89.5 37.6 RS35 Mataikona Trib at Sugar Loaf Rd 130.6 7.03 73.2 58 RS36 Taueru R at Castlehill 110.5 5.07 48.6 42.8 RS37 Taueru R at Gladstone 89.5 4.41 12.9 32.5 RS38 Kopuaranga R at Stewarts 95 3.95 37.4 34 RS39 Whangaehu R 250m u/s confl. 76.9 4.09 0.2 5 RS40 Waipoua R at Colombo Rd Br 103.6 4.23 48.3 40.4 RS41 Waingawa R at South Rd 113.3 6.82 76.3 49.3 RS42 Whareama R at Gauge 80.2 3.98 0.4 14.8 RS43 Motuwaireka S at Headwaters 130 6.79 60.4 58.3 RS44 Totara S at Stronvar 98.9 4.55 48.8 35.3 RS45 Parkvale Trib at Lowes Reserve 101 4.74 25.5 36.3 RS46 Parkvale S at Weir 75.9 3.39 6.2 19.5 RS47 Waiohine R at Gorge 139.2 7.88 92.4 69 RS48 Waiohine R at Bicknells 116.5 6.56 72.9 50 RS49 Beef Ck at Headwaters 133.3 7.28 75 58.4 RS50 Mangatarere S at SH 2 96.9 4.58 27 34.5 RS51 Huangarua R at Ponatahi Br 95.5 4.11 57.8 30 RS52 Tauanui R at Whakatomotomo Rd 129.8 6.74 75.3 59.7 RS53 Awhea R at Tora Rd 97.2 5.75 39.3 23.4 RS54 Coles Ck Trib at Lagoon Hill Rd 107.6 5.19 30.2 31.1 RS55 Tauherenikau R at Websters 118.7 7.15 86.9 47.5 RS56 Waiorongomai R at Forest Pk 124.8 7.14 81.9 54.4 1 Scores presented for these sites are based only samples results from 2009 and 2010 only. The 2011 sample results were influenced by a small fresh at the time of sampling. PAGE 78 OF 160 WGN_DOCS-#1100598-V3
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River and stream water quality and
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DISCLAIMER This report has been pre
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observed trends were unclear. The p
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5. Periphyton - state and trends 57
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Figure 2.1: RSoE monitoring sites a
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2.4.2 Biological variables River an
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