STREAM ECOLOGICAL VALUATION FOR THE PROPOSED NIKAU PALM ROAD CLEANFILL AT PARAPARAUMU

Transcription

1 STREAM ECOLOGICAL VALUATION FOR THE PROPOSED NIKAU PALM ROAD CLEANFILL AT PARAPARAUMU R3113

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3 STREAM ECOLOGICAL VALUATION FOR THE PROPOSED NIKAU PALM ROAD CLEANFILL AT PARAPARAUMU Koura (Paranephrops planifrons) from Nikau Gully Stream, February May 2013 Project Team: Nick Goldwater - Report author, field survey, SEV analysis, and report author Frances Forsyth - Field survey and report author Prepared for: Goodman Contractors Ltd C/- Cuttriss Consultants Ltd 33 Kapiti Road, Paraparaumu, P.O. Box 386 Paraparaumu. WELLINGTON OFFICE: 7A SUNLIGHT GROVE, ELSDON, P.O. BOX , PORIRUA Ph ; Fax HEAD OFFICE: 99 SALA STREET, P.O. BOX 7137, TE NGAE, ROTORUA Ph ; Fax , ecology@wildlands.co.nz,

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5 CONTENTS 1. INTRODUCTION 1 2. EXTENT OF PROPOSED WORKS 1 3. METHODS Freshwater fish Freshwater invertebrates Stream Ecological Valuation 2 4. FAUNA Fish Aquatic macroinvertebrates Nikau Gully Stream Mazengarb Drain 6 5. STREAM ECOLOGICAL VALUATION Nikau Gully Stream (impact site) Mazengarb Drain (Compensation Stream) 7 6. OPPORTUNITIES TO AVOID, REMEDY OR MITIGATE ADVERSE ECOLOGICAL EFFECTS Compensation for the loss of permanent stream habitat 7 ACKNOWLEDGMENTS 11 REFERENCES 11 APPENDICES 1. List of macroinvertebrates recorded from the impact and compensation streams SEV results for the impact and compensation streams Site photographs 12

6 Reviewed and approved for release by: W.B. Shaw Director/Principal Ecologist Wildland Consultants Ltd Wildland Consultants Ltd 2013 This report has been produced by Wildland Consultants Ltd for Goodman Contractors Ltd. All copyright in this report is the property of Wildland Consultants Ltd and any unauthorised publication, reproduction, or adaptation of this report is a breach of that copyright.

7 1. INTRODUCTION Cuttriss Consultants Ltd, on behalf of Higgins Aggregates Ltd and Goodman Contractors Ltd, is applying to Kapiti Coast District Council and Greater Wellington Regional Council for resource consents to create a new cleanfill site between Paraparaumu Quarry and Nikau Palm Road, at Paraparaumu. Wildland Consultants Ltd were commissioned to undertake a Stream Ecological Valuation (SEV) of a reach of stream that will be affected by the proposed cleanfill, using the approach provided in Auckland Council Technical Report 2011/009. SEV is a method for scoring the ecological condition of streams and for quantifying environmental compensation. This method was reviewed by NIWA for use in Wellington streams in Due to the permanent nature of the effects of the proposed landfill, and the limited length of the non-affected stream channel within the property boundary, on-site instream compensation may not be feasible. As a result, a potential compensation reach, in a downstream section of the Mazengarb Drain, has also been surveyed. Data from both of these sites is required in order to satisfy the criteria for an SEV assessment. This report provides a description of the stream survey undertaken, the SEV analysis, and the findings from this work. 2. EXTENT OF PROPOSED WORKS The proposed cleanfill will proceed in three stages, beginning at the head of the gully (Figure 1). Only the third stage will directly affect the stream, which lies at the bottom of the gully and is fed by a seepage wetland. Approximately 75 m of stream length will be piped in order to facilitate the construction of the clenfill. Earlier stages will alter the hydrological response of the catchment as wetland storage is progressively lost and culverts are installed to divert surface water flow around and under the cleanfill. Each stage will require a sediment retention pond, with the pond for stage three lying directly in the path of the existing stream channel. 3. METHODS The Stream Ecological Valuation was carried out on 28 February Stream habitat, fish, and macroinvertebrates were surveyed and the data was analysed. Representative photos are presented in Appendix Freshwater fish Freshwater fish were sampled using an electro-fishing unit and following the backpack electro-fishing procedure described in David and Hamer (2010). 1

8 3.2 Freshwater invertebrates Samples of freshwater macroinvertebrates were collected throughout the streams, using a kick-net. The kick-net was used to capture macroinvertebrates from the water column, the stream bed sediments, and on submerged vegetation and woody debris. Samples were preserved in ethanol for later analysis in a laboratory, where they were identified and counted (Appendix 2). 3.3 Stream Ecological Valuation Stream Ecological Valuation (SEV) is a comprehensive method for quantifying the value of aquatic ecosystems. This method uses a range of qualitative and quantitative variables to assess the main ecological functions of streams. This data is then manipulated using a series of formulae in order to produce an SEV score of between 0 (a stream with no ecological value) and 1 (a pristine stream with maximum ecological value). The method allows even very different streams to be evaluated and compared. A Stream Ecological Valuation (SEV) assesses the performance of 14 stream functions, divided into four categories (Table 1). Each function is weighted equally with the resultant SEV score being the mean function score (the sum of all function scores divided by 14). These function scores enable stream and catchment managers to understand the range of ecological services a stream provides. When used in conjunction with an SEV of a second stream proposed as a site for offsetting, the SEV scores are used to determine an Environment Compensation Ratio, which in turn is used to calculate the total stream area to be compensated. Table 1: Summary of the 14 ecological functions used to calculate the SEV score. Hydraulic Functions (Processes associated with water storage, movement and transport) 1. Natural flow regime 2. Floodplain effectiveness 3. Connectivity for natural species migrations 4. Natural connectivity to groundwater Biogeochemical Functions (Relates to the processing of minerals, particulates and water chemistry) 5. Water temperature control 6. Dissolved oxygen maintained 7. Organic matter input 8. In-stream particle retention 9. Decontamination of pollutants Habitat Provision (The types, amount and quality of habitats that the stream reach provides for flora and fauna) 10. Fish spawning habitat 11. Habitat for aquatic fauna Biotic Functions (The occurrence of diverse populations of indigenous native plants and animals that would normally be associated with the stream reach) 12. Fish fauna intact 13. Invertebrate fauna intact 14. Riparian vegetation intact Field work includes a comprehensive range of quantitative and qualitative assessments of the stream and riparian environment. Data collection involves aquatic macroinvertebrate sampling, a fish survey, flow gauging, in-stream particle retention experiment, analysis of stream channel morphology (width, depth, and substrate particle size, or roughness) from ten transects across the stream, as well as a critical visual assessment of the entire reach recording a range of parameters. Field data is complemented by desktop information such as impervious surfaces, flooding frequency, and catchment size. 2

9 Figure 1: Map showing the extent of the three stages of the cleanfill and the length of stream that will be affected. 3

10 The SEV method was first developed by a panel of experts (Rowe et al. 2006) for the Auckland Regional Council. It is the recommended method for assessing streams in Auckland and Wellington but has also been successfully applied in other parts of New Zealand. The SEV method was revised in 2011 and consequently is simpler and more efficient to carry out, yet has not lost any important information. The full SEV method, including all formulae and algorithms, is described in Storey et al. (2011). Note that for this particular study, the SEV calculator has been updated with values that are relevant for Wellington rocky bottom streams. The formulae are all the same as the standard SEV calculator, but values in Vphyshab, Vsurf, and taxa lists in Vmci and Vinvert are all appropriate to Wellington streams (R. Storey, NIWA, pers. comm. 2012). It should be noted that SEV calculations for the Nikau Gully stream and Mazengarb Drain were carried out in the absence of a suitable reference stream(s). There were no soft-bottomed reference streams in the Kapiti District available during the production of this report. The lack of reference streams is an issue that needs to be addressed by Greater Wellington Regional Council if the SEV method is to be used effectively throughout the region. In saying that, however, the SEV manual states that it is still possible to conduct SEV in streams where no equivalent reference sites are available. One option is to develop a hypothetical reference site that combines reference conditions from a variety of streams that are each unmodified in terms of particular functions. For the purposes of this report, data from two hypothetical reference streams were used to (i) simulate a site with greater than 95% indigenous forest cover within the same catchment and to (ii) simulate the test site (Nikau Gully stream) in an ecologically intact condition. The data for the two reference sites are presented in Appendix FAUNA 4.1 Fish Nikau Gully Eight banded kōkopu (Galaxias fasiculatus) and one unidentified eel (Anguilla sp.) were found. Mazengarb Drain More than 20 inanga (Galaxias maculatus), more than 20 common bully (Gobiomorphus cotidianus), and one unidentified eel (elver). Inanga are classified as At Risk-Declining by Allibone et al. (2010). A search of the New Zealand Freshwater Fish Database revealed only one record for the Mazengarb Drain, dated July 2006 (Figure 1). This record is for a small lake in the urban part of the catchment (Card number 15190). Shortfin eel (Anguilla australis) were recorded as abundant; common bullies (Gobiomorphus cotidianus) as occasional, and there was one common smelt (Retropinna retropinna). 4

11 The Greater Wellington Regional Council predicted fish distribution tool (Accessed online) indicates that neither the lower nor upper reaches of the Mazengarb catchment are likely to support more than a low diversity of fish species. Figure 1: Sites in the Waikanae River catchment with records in the NZ Freshwater Fish Database at March This includes the one record from the Mazengarb Drain. The site of the proposed cleanfill is at the tip of the arrow. 4.2 Aquatic macroinvertebrates Nikau Gully Stream The diversity of aquatic macroinvertebrate fauna in the stream was relatively low, with 11 taxa recorded. Crustaceans were by far the most abundant group of macroinvertebrates, largely represented by koura (Paranephrops planifrons) and amphipods, including individuals in the genus Paraleptamphopus. All other taxa were represented by either single or low numbers of individuals. The abundance of koura, which have a high tolerance score of 8.4, indicates good stream conditions. The number of koura, however, would likely to be significantly lower in the presence of large predators such as eels. Koura is classified as At Risk-Declining, as per Hitchmough et al. (2007). 5

12 The soft-bottomed MCI score for the Nikau Gully Stream is 98.6, which is indicative of fair biological quality (Stark and Maxted 2007). Full macroinvertebrate results are provided in Appendix 1. Mazengarb Drain The diversity of aquatic macroinvertebrate fauna in the Mazengarb Drain was also relatively low, with 14 taxa recorded. Most of the taxa recorded from the site are tolerant of poor stream conditions, including oligochaete worms and leeches. Other taxa well-represented in the sample include amphipods in the genus Paracalliope, which are abundant in many lowland, slow-flowing weedy streams and are tolerant of a wide range of conditions. Polypedilum midge larvae were the most numerous taxon in the sample. Polypedilum larvae have a high tolerance score of 8.0, a result that contrasts with the rest of the sample. The soft-bottomed MCI score for Mazengarb Drain is 68.9, which is indicative of poor biological quality (Stark and Maxted 2007). 5. STREAM ECOLOGICAL VALUATION 5.1 Nikau Gully Stream (impact site) The SEV score for the Nikau Gully stream impact site is This is a moderate score, reflecting that most of the stream is in a relatively natural state, is well-shaded, and contains some stable habitat for aquatic fauna. The stream scored low to moderate for hydraulic function (0.47), which acknowledges the natural channel and the absence of piped inflows. The overall score, however, was lowered by the lack of connectivity to the floodplain due to channel incision together with the unnatural loading of fine sediment and barriers to migration. The stream scored relatively high for biogeochemical function (0.69), which reflects the high level of shading provided by the mixed indigenous-exotic canopy (and absence of deciduous vegetation), the heterogeneity of the streambed substrate, the lack of macrophytes present in the stream, and the natural state of the channel. Habitat provision for indigenous fish scored reasonably well (0.60), which reflects the good quality of spawning habitat for bully (Gobiomorphus) species, the lack of impervious surfaces in the catchment, and the presence of stable habitat such as undercut banks, cobbles, gravels and woody debris. The overall score was lowered by the lack of shading upstream of the study reach and the poor spawning habitat for galaxiids (Galaxias spp.). The biodiversity function score (0.32) is the lowest of all functions, which reflects a poor Index of Biological Integrity (IBI) for fish (20), a moderate Macroinvertebrate Community Index (MCI) score, and a low richness of EPT (Ephemeroptera, Plecoptera, Trichoptera) taxa. The low IBI for fish is evidence of a barrier to fish passage downstream of the site. Note that the biodiversity function score is likely to 6

13 be artificially lowered due to the lack of invertebrate data from a soft-bottom reference stream in the Kapiti area. Full SEV results for both streams are presented in Appendix Mazengarb Drain (Compensation Stream) The SEV score for the potential compensation site in the Mazengarb Drain is This is a poor score, reflecting a highly channelised watercourse that lacks riparian shading and flows through a landscape dominated by impervious surfaces. The stream scored low to moderate for hydraulic function (0.44), which acknowledges that the entire stream channel has been straightened and deepened. It also reflects a lack of connectivity with the floodplain, the presence of piped inflows, and the lack of riparian vegetation. The score was buffered by the fact that there are no barriers to migration in the stream. Unsurprisingly, the stream scored poorly for biogeochemical function (0.30), which points to the near absence of shading provided by riparian vegetation, the low amount of filtering activity provided by surrounding vegetation, and the abundance of submerged macrophytes. Habitat provision for indigenous fish also scored very low (0.12), which acknowledges the lack of stable physical habitat for bullies and galaxiids, the lack of shading upstream of the study site, and high levels of impervious surfaces in the catchment. Similarly, the biodiversity function score was very low (0.13). The score was affected by a poor Index of Biological Integrity (IBI) for fish (20), a poor MCI score and the absence of EPT taxa. As with the impact stream, the biodiversity function score for Mazengarb Drain is likely to have been artificially lowered due to the lack of invertebrate data from a soft-bottom reference stream in the Kapiti area. 6. OPPORTUNITIES TO AVOID, REMEDY OR MITIGATE ADVERSE ECOLOGICAL EFFECTS 6.1 Compensation for the loss of permanent stream habitat The Environmental Compensation Ratio (ECR) can be applied where a stream is to be degraded, to ensure that there is no net loss in ecological value. The ECR determines the length of stream that needs to be restored relative to the length of stream to be degraded, taking into account the relative ecological quality of each stream. In situations where restoration is not possible, the ECR can also be used to determine the amount of financial compensation required (Rowe et al. 2006). Where a stream reach to be degraded is similar to a reach that will be restored then, assuming full restoration is possible over a short timeframe, a theoretical ECR close to 1:1 may be warranted. However, where the stream to be restored is lower in ecological value than the reach being degraded, the ratio needs to be set at a higher 7

14 level to compensate for this. Therefore, it may be necessary to restore three or four times the length of stream to be degraded. The ECR equation compares two streams and also takes into account the time delay inherent when a stream is planted before full benefits are realised. It also takes into account the possible failings or inadequacies often encountered in restoration projects. The formulae to calculate the ECR is: ECR = Predicted loss of function Predicted gain after restoration 1.5 delay factor The predicted gain assumes best practice restoration is followed on the streams to be restored. Note that the ECR excludes biotic scores (function numbers 12 and 13) as these are too difficult to predict. Calculations Table 2: Existing and predicted SEV scores following restoration. Site Name Existing Function Score (SEV - Biotic Functions) Predicted Score Following Restoration Predicted Score Following Impact Predicted Loss of Function Predicted Gain Through Restoration Impact stream Compensation Stream n/a n/a Stream Areas The areas of the two streams have been calculated and are presented in Table 3 below. Table 3: Area of impact and compensation streams. Site Name Average Wetted Width (m) Length (m) Stream Area (m 2 ) Impact stream Compensation Stream Level of Compensation In order to compensate for the loss of the impact site: ECR = (0.595/0.201) 1.5 = 4.44 This means that 4.44 times the area of the impact stream needs to be restored to result in no net loss of function. The area to be lost from the removal of the impact stream is 42.8 m 2. The total area required to be restored using an ECR of 4.44 is 190 m 2, which equates to 48 m of stream length to be restored (i.e. 190 m 2 divided by an average width of the 8

15 compensation stream, which is 4 m). It is unusual for the compensation stream length to be less than that of the impact reach; however, in this case the average width of the Mazengarb Drain is significantly greater than that of the Nikau Gully stream (i.e. 4 m vs m). A common perception of piped stream reaches is that they no longer have any biotic value whatsoever. For this reason it has been standard practise for some practitioners to apply an SEV score of zero to the impacted reach. However, personal observations by the authors show that banded kōkopu downstream from a pipe regularly utilise the upstream cover and habitat it provides. In the instances that pipes have risers with gratings rather than sealed covers if is not unusual to observe galaxiids in the pipe below from the top of the riser. We have also taken into account the fact that piped streams are 100% shaded keeping water cool and maintaining dissolved oxygen levels. For this reason we believe that a score of zero should not always be applied. There have been significant constraints regarding the selection of an appropriate compensation reach for this project. While the proposed compensation is not like for like it is as close to this as possible while remaining in the Mazengarg Drain catchment and the site has the benefit of permanent protection under the Reserves Act. Neither of the neighbouring catchments (Wharemauku and Muaupoko) has suitable sites for applying compensation measures. While enhancing this reach will not offer permanent habitat for banded kōkopu it will offer enhanced migration opportunities for them and other species. Mazengarb tributaries within Nikau Reserve, in the sub-catchment next to the proposed cleanfill, will benefit from enhanced fish migration. The Mazengarb Drain is a degraded waterway and it is probable that restoration of only 48 m will not result in any appreciable improvement to the stream. However, this is the second rehabilitation project in several years and it is likely that, in a relatively short time, further rehabilitation of this reach of the Mazengarb Drain will take place both as a result of more restoration projects arising from future impacts in the catchment and as part of KCDC s biodiversity enhancement programme. While the first stages of such rehabilitation work are likely to show few improvements for biodiversity it is important to understand that the cumulative effects of restoring riparian vegetation to the entire reach would be significant. The standard riparian planting process will need to be modified in order for KCDC Flood Protection staff to access the stream channel along the restored reach. The Flood Protection team currently manages the stream channel by excavating aquatic plants, algae and some stream sediment. Such access can be accommodated by providing 3 m accessways for a digger on one side of the stream between nodes of riparian planting (four nodes, each approximately 10x10 m). Planting on the opposite bank would then be wider than usual (15 m rather than 10 m) to compensate for that. All plantings should include a mix of tall shade trees such as totara (Podocarpus totara), ngaio (Myoporum laetum) and kanuka (Kunzea ericoides var. ericoides), mixed 1 with akeake (Dodonaea viscosa) for shelter and frost protection. Some 1 For instance the 48x14 m strip (excluding a row of bankside sedges at 0.7 m spacings) will require 211 akeake and 73 in total of totara, ngaio and kanuka at 1.5 m spacings. The 10x10 m plots will contain 33 akeake and a total of 8 of the other three species with a band of sedges along the stream bank. 9

16 akeake may be replaced with harakeke (Phormium tenax) close to the stream and with cabbage tree (Cordyline australis) further from the stream. The stream edge should be planted with sedges, Carex virgata where the banks are high, and therefore very dry, and C. secta where the plants will be close enough to have their roots in a permanently moist substrate. It is expected that such plantings will have a high level of success compared with an earlier project on the Mazengarb Drain. For that project the number of plants required had been mis-calculated so that insufficient numbers were planted, and some of the species selected were inappropriate for the site. It has been proposed that at some time in the future KCDC Flood Protection will change to an alternative management regime involving a weed harvester of a type similar to those illustrated in Figure 2. This will allow the digger access routes to be closed off and planted. In the meantime the increasing shade over the stream provided by the riparian planting will also reduce weed growth. Since riparian planting has developed and created a canopy over the neighbouring Wharemauku Stream it has been observed that aquatic plants and algae have disappeared. Figure 2: Examples of small weed harvester machines (multiple internet sources). Riparian planting alone cannot address the issue of poor water quality in the Mazengarb Drain, which is itself a product of levels of impervious surfaces in the catchment and inputs of pollutants. However, it is likely that such issues will be addressed in the future as residents become more aware of the harm done by poor water quality and the solutions available. In combination with riparian planting, the application of low impact urban design principles will result in both enhanced biodiversity and environmental values. As mentioned earlier, such improvements will occur incrementally with little, or no, improvement observed initially. However, as further steps are made towards the goal, the benefits of each step will become measurable. 6.2 Fish translocation Should the proposed cleanfill proceed, indigenous fish from the Nikau Gully Stream must be translocated to suitable habitat, preferably in the same catchment. This will be carried out using a combination of electric fishing, kick-netting and setting fyke nets and minnow traps. Koura will also be translocated. An indicative fish rescue plan is presented below: 10

17 (i) Fish the stream using an electric fishing unit and several scoop nets. Translocate fish to a suitable stream. Set baited fykes nets and minnow nets and leave overnight. (ii) On the following day, return to site and transfer fish captured in the nets and/or traps to the relocation site. Fish the stream using an electric fishing unit and several scoop nets. Transfer any fish. (iii) Prepare draft report on the above fish translocation, including photographs and species lists, and supply to client. If fish need to be relocated to a stream in a different catchment where other fish of that species already occur, a permit will be required from the Biosecurity section of the Ministry for Primary Industries (Steve Pullan, Ministry for Primary Industries, pers. comm. 22 March 2013). A Department of Conservation permit is required (Rosemary Miller, Department of Conservation, pers. comm. 18 March 2013) when fish are relocated to another catchment where that species is not already present. ACKNOWLEDGMENTS We would like to thank Cuttriss Consultants Ltd for organising multi-party meetings so that all technical experts, and regional and district council officers working on this project could collaborate and find workable solutions for issues at the project and compensation sites. REFERENCES Alibone R., David B., Hitchmough R., Jellyman D., Ling N., Ravenscroft P. and Waters J. 2010: Conservation status of New Zealand freshwater fish New Zealand Journal of Marine and Freshwater Research 44(4): David B. and Hamer M. 2010: Regional guidelines for ecological assessments of freshwater environments: standardised fish monitoring for wadeable streams. Environment Waikato Technical Report 2010/09. Greater Wellington Predicted freshwater fish distribution tool. Available as part of the Greater Wellington public mapping service. Hitchmough R., Bull L., and Cromarty P. (Compilers) 2007: New Zealand threat classification system lists Department of Conservation. Rowe D., Quinn J., Parkyn S., Collier K., Hatton C., Joy M., Maxted J., and Moore S. 2006: Stream ecological valuation (SEV): a method for scoring the ecological performance of Auckland streams and for quantifying mitigation. Report prepared by NIWA for Auckland Regional Council. Stark J.D. and Maxted J.R. 2007: A user guide for the macroinvertebrate community index. Prepared for the Ministry for the Environment. Cawthron Report

18 Storey R., Neale M., Rowe d., Collier K., Hatton M., Joy M., Maxted J., Moore S., Parkyn S., Phillips N., and Quinn J. 2011: Stream ecological valuation (SEV): a method for assessing the ecological function of Auckland streams. Auckland Council Technical Report 2011/009. APPENDIX 1 SITE PHOTOGRAPHS 12

19 Plate 1: Head of the stream at the impact site. This is where the stream channel is first defined at the bottom of the seepage wetland. The stream enters the pine forest at the right of the image. Plate 2: Part of the SEV survey site within the Nikau gully stream. 13

20 Plate 3: Koura (Paranephrops planifrons) caught in the Nikau Gully stream. Plate 4: Adult banded kōkopu (Galaxias fasiculatus) caught in the Nikau Gully stream. 14

21 Plate 5: View upstream along the Mazengarb Drain, at the SEV survey site. Plate 6: Adult common bully (Gobiomorphis cotidianus) (bottom) and adult inanga (Galaxias maculatus) (top) caught in the Mazengarb Drain. 15

22 Plate 7: Juvenile inanga caught in the Mazengarb Drain. 16

23 APPENDIX 2 LIST OF MACROINVERTEBRATES RECORDED FROM THE IMPACT AND COMPENSATION STREAMS 27 February 2013 Taxa MCI MCI-sb Ephemeroptera score score Nikau Cleanfill Stream Austronella Odonata Mazengarb Drain Xanthocnemis Hemiptera 1 Coleoptera Elmidae Diptera Austrosimulium Chironomidae Empididae Orthocladiinae Polypedilum Tipulidae Lepidoptera Hygraula Crustacea Amphipoda Ostracoda Paracalliope Paraleptamphopus Paranephrops Paratya Talitridae MOLLUSCA Ferrissia Lymnaeidae Potamopyrgus OLIGOCHAETA HIRUDINEA PLATYHELMINTHES Hydra Number of Taxa Total individuals EPT Taxa 1 0 EPT individuals 1 0 MCI-sb Value

24 APPENDIX 3 SEV RESULTS FOR THE IMPACT AND COMPENSATION STREAMS Function Category Function Variable (code) Nikau Gully Stream Mazengarb Drain Vchann Vlining Vpipe Hydraulic NFR = Vbank Vrough Hydraulic FLE = Vbarr Hydraulic CSM = Vchanshape Vlining Hydraulic CGW = Hydraulic function mean score Vshade Biogeochemical WTC = Vdod Biogeochemical DOM = Vripar Vdecid Biogeochemical OMI = Vmacro Vretain Biogeochemical IPR = Vsurf Vripfilt Biogeochemical DOP = Biogeochemical function mean score Vgalspwn Vgalqual Vgobspwn

25 Function Category Function Variable (code) Nikau Gully Stream Mazengarb Drain Habitat provision FSH = Vphyshab Vwatqual Vimperv Habitat provision HAF = Habitat provision function mean score Vfish Biodiversity FFI = Vmci Vept Vinvert Biodiversity IFI = Vripcond Vripconn Biodiversity RVI = Overall mean SEV score (maximum value 1) Biodiversity function mean score

26 APPENDIX 4 PREDICTED SEV SCORES FOR NIKAU GULLY STREAM AND MAZENGARB DRAIN FOLLOWING IMPACT AND RESTORATION Function Category Function After After After impact Variable (code) restoration restoration (Nikau Gully) (Nikau Gully) (Mazengarb) Vchann Vlining Vpipe Hydraulic NFR = Vbank Vrough Hydraulic FLE = Vbarr Hydraulic CSM = Vchanshape Vlining Hydraulic CGW = Hydraulic function mean score Vshade Biogeochemical WTC = Vdod Biogeochemical DOM = Vripar Vdecid Biogeochemical OMI = Vmacro Vretain Biogeochemical IPR = Vsurf Vripfilt Biogeochemical DOP = Biogeochemical function mean score Vgalspwn Vgalqual Vgobspwn

27 After After Function After impact Function Variable (code) restoration restoration Category (Nikau Gully) (Nikau Gully) (Mazengarb) Habitat provision FSH = Vphyshab Vwatqual Vimperv Habitat provision HAF = Habitat provision function mean score Vfish Biodiversity FFI = Vmci Vept Vinvert Biodiversity IFI = Vripcond Vripconn Biodiversity RVI = Biodiversity function mean score Overall Mean SEV Score (maximum value 1)

28 APPENDIX 5 PREDICTED SEV RESULTS FOR TWO REFERENCE STREAMS Function Category Function Variable (code) Stream 1 Stream 2 Vchann Vlining Vpipe Hydraulic NFR = Vbank Vrough Hydraulic FLE = Vbarr Hydraulic CSM = Vchanshape Vlining Hydraulic CGW = Hydraulic function mean score Vshade Biogeochemical WTC = Vdod Biogeochemical DOM = Vripar Vdecid Biogeochemical OMI = Vmacro Vretain Biogeochemical IPR = Vsurf Vripfilt Biogeochemical DOP = Biogeochemical function mean score Vgalspwn Vgalqual Vgobspwn Habitat provision FSH =

29 Function Category Function Variable (code) Stream 1 Stream 2 Vphyshab Vwatqual Vimperv Habitat provision HAF = Habitat provision function mean score Vfish Biodiversity FFI = Vmci Vept Vinvert Biodiversity IFI = Vripcond Vripconn Biodiversity RVI = Overall mean SEV score (maximum value 1) Biodiversity function mean score

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