Mapping Wellington's Unpiped Streams/media/about-wellington/research-and... · To accurately map...

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Victoria University Summer Scholarship 2012/2013 Mapping Wellington's Unpiped Streams: Myren Burnett Supervisors: Amber Bill & Robin Skinner

Executive Summary Between November 2012 and March 2013 400 hours was dedicated to researching, identifying and mapping Wellington's unpiped streams. There were dozens of streams in the central Wellington region to be mapped, and this project aimed to establish a single database where all stream information could be stored. The goals for the project were kept simple because of time constraints: accurately map the first and second order streams of central Wellington, including Karori and everywhere to the south and east of Kaiwharawhara stream. Digitize that map data and produce a database for storing the stream locations and various important physical attributes. Research methods included literary sources, archive searches, interviews with WCC staff and knowledgeable members of the public, as well as online searches. Field mapping was done with a portable GPS and data was organised and stored within the council GIS network using a combination of ArcMap and ArcCatalogue. Because of the challenging topography of Wellington, and private land access, there were some streams which were unable to be mapped within this project. All of these locations have been noted within the GIS database so that they can be revisited in the future if necessary. The database is editable, and data can be continuously added to embellish the council's stream data as it becomes available. Stream data has uses for a wide variety of council departments and other parties, so it is important that the data be clearly and easily accessible. Stream data is stored within the Biophilic City folder, under the heading 'Stream Capture'. This project has strengthened and clarified the council's existing knowledge of Wellington's streams, and it had added significant new knowledge as well. 65 unpiped streams were confirmed and mapped over the course of the project, with several separate segments for many streams. 62 of these streams were previously unmapped (or mapped inaccurately) within the council GIS database. Nearly 17,000m of unpiped stream has been mapped so far. One of the most useful and efficient methods of research was through contacting community groups involved in the management of public spaces. In addition t their significant first-hand knowledge of areas of Wellington many of these groups (or individuals within them) were eager to engage with the council and shared much valuable information that allowed these areas to be mapped in greater detail and much more quickly than would otherwise have been possible. For the future mapping of Wellington's streams it is recommended that the knowledge of community groups be tapped into generously.

Mapping Wellington's Unpiped Streams: Myren Burnett

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Table of Contents Executive Summary ................................................................................................................... 1 Table of Contents ...................................................................................................................... 2 1. Problem Statement ................................................................................................................ 3 2. Aim of Project ........................................................................................................................ 3 3. Methodology (How the Aim was met / redefined) .................................................................. 3

3.1 Strategies ......................................................................................................................... 3 3.1.1. Define Boundaries and Goal Areas .......................................................................... 4 3.1.2. Compile Data / Sources ........................................................................................... 4

3.2. Sources ........................................................................................................................... 5 3.3. Data Analysis .............................................................................................................. 6 3.4. Generate Hypothesis ................................................................................................... 6 3.5. Stream Attribute List .................................................................................................... 6 3.6. Ground Truthing .......................................................................................................... 7 3.7. Digitise Information ...................................................................................................... 7 3.8. Response to Data – Diagnose Knowledge Gaps ........................................................ 7 3.9. Discussion with Iwi and other Relevant Parties .......................................................... 7

4. Outcomes: ............................................................................................................................. 8 4.1. Existing Knowledge confirmed/strengthened .................................................................. 8

4.1.1. Existing water courses accurately mapped .............................................................. 8 4.1.2. Connections with piped network established ........................................................... 8

4.2. New Knowledge Outcomes: Water Courses Mapped .................................................... 8 4.2.1. Total Number of Unpiped Streams Confirmed + Mapped: 65 (Fig. 1) ..................... 8 4.2.2. Total Amount (metres) of Unpiped Stream Mapped: 16,695m ................................ 8 4.2.3. Number of Previously Unmapped Streams: 62 ........................................................ 8 4.2.4. Number of Mapped Streams By Location: ............................................................... 8 4.2.5. Priority areas to be investigated ............................................................................... 8

5. Gaps in Current Knowledge .................................................................................................. 9 5.1. Cross disciplinary project ............................................................................................ 9 5.2. Inter-departmental knowledge gaps ............................................................................ 9 5.3. Strategy to address gaps ............................................................................................ 9 5.4. Clear Methodology for future work ............................................................................ 10

6. Conclusion + Maps .............................................................................................................. 11 Figure 1: Wellington's Unpiped Streams .......................................................................... 12 Figure 2: Kelburn + Thorndon Confirmed Streams .......................................................... 13 Figure 3: Aro Valley + Mt. Cook Confirmed Streams ....................................................... 13 Figure 4: Newtown + Berhampore Confirmed Streams ................................................... 14 Figure 5: Owhiro Valley + Brooklyn Confirmed Streams .................................................. 14 Figure 6: Northland Confirmed Streams .......................................................................... 15 Figure 7: Houghton Valley Confirmed Streams ................................................................ 15 Figure 8: Karori Confirmed Streams ................................................................................ 16 Figure 9: Miramar Peninsula Confirmed Streams ............................................................ 16 Figure 10: Karori Stream Estimates ................................................................................. 17 Figure 11: Newlands Stream Estimates ........................................................................... 17 Figure 12: Khandallah Stream Estimates ......................................................................... 18


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1. Problem Statement Wellington has a large number of hills and valleys within its urban fabric, and as a result, a large number of streams and natural waterways. Urban gullies have been filled in and streams straightened or piped to accommodate development. These streams have not been mapped through the development of the city, meaning that Wellington City Council, or any other organisation, does not have an accurate and singular database showing the locations and typologies of local, existing or historic, waterways.

2. Aim of Project To accurately map the first and second order streams of central Wellington, including both piped and unpiped streams.

3. Methodology (How the Aim was met / redefined)

3.1 Strategies

• Define Boundaries and Goal Areas (Revise in response to time constraints and new info)

• Compile Data / Sources

• Data Analysis

• Generate Hypothesis

• Ground-Truthing

• Digitise Information

• Response to Data – diagnose knowledge gaps

• Reflection and future work

• Discussion with relevant / interested parties


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3.1.1. Define Boundaries and Goal Areas Physical boundaries

• Central Wellington is initial focus – inside town belt • Boundaries – Kaiwharawhara Stream is north-west boundary, Owhiro Stream to the

south-west. Miramar and South Coast complete initial mapping area. • By utilising knowledge from public input it will be possible to map a larger area in

greater detail than relying entirely on personal mapping. Academic boundaries: Extent of project

• To make the most of a limited time-frame (400 hours) and a weather sensitive mapping process the project was defined as ‘Accurately mapping the first and second order streams of central Wellington.’ This allowed the scope of the project to cover more physical area, and produce a reliable, concise dataset which can be amended and added to in the future.

• 'Unpiped Streams' were defined as those which were permanently flowing, open to the air, and first or second order (meaning they flowed directly to the sea, or were a tributary into those streams).

3.1.2. Compile Data / Sources There are many streams that are known but not mapped accurately. Task one is to identify these streams for mapping. Second task is to produce a map of currently unconfirmed/potential stream locations and to ground-truth these sites. Prominent identified streams include:

• Kaiwharawhara • Owhiro • Houghton Valley • Kumutoto • Moturua • Waimapihi • Wai-paekaka • Pipitea • Waipiro • Te Mahanga • Korimako

These streams have been named and identified in the past, but many of the watercourses have been altered by Wellington’s underground pipe network, meaning that locations and correct names have in many cases been lost. To produce a map of potential stream locations, research was conducted into first-hand accounts, historical maps and literature, WCC GIS data, physical maps, pipe network data and extensive public knowledge.


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3.2. Sources

• ‘The Great Harbour of Tara’- Adkin

• Stream Quality Assessments (WCC)

• WCC Asset Management Data (GIS)

• WCC Staff Input: Parks, Sport & Recreation, InfoNet, Biophilic City/Our Living City

• Stream Quality Monitoring Websites

• Local Iwi

• Aerial Photos

• Historic Photos

• Alexander Turnbull Library Collection: Historic Maps

• National Library of New Zealand (NatLib)

• NIWA

• NatLib: Big Data

• First-Hand Field Work

WCC Staff Input

• Amber Bill • Nicci Wood • Tracey Mauchlen • Alex Robertson • Thomas Nation • Martyn Simpson • Sean Audain • Myfanwy Emeny • Michael Brownie • Pualo Fuiono • Myfanwy Eaves • Nick Page (Regional Council)

Public Input

• Chris Horne • Grant Corbishley • Frances Forsyth • Bev Abbott


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3.3. Data Analysis The compiled information was displayed graphically, and sorted into categories – confirmed, estimated, historical etc – which were layered against maps showing topography, hard surfaces and pipes to identify gaps in the pipe network and locations which were likely to contain unpiped streams. Three key sources for this stage were first-hand accounts of the physical environment, G. L. Adkin’s book ‘The Great Harbour of Tara’, and the pipe network, gaps in which indicate the presence of streams, either ephemeral or permanently flowing.

3.4. Generate Hypothesis The analysis produced a map of estimated stream locations using the stream centreline, which was to be ground-truthed and the results digitised. InfoNet staff are planning to map these waterways in greater detail in the future. In addition to mapping the centrelines a second map layer was created to map stream features; points along the course of a stream which provide additional information as to the nature of that stream. Features include (but are not limited to):

• Secondary tributaries • Culverts • Dams • Stream breaks • Artificial interventions • Broken Pipes • Stormwater drains • Details of the beginnings of a stream

3.5. Stream Attribute List A series of stream attributes were defined as important for the mapping process. For each attribute a series of clear definitions was agreed upon to ensure consistency across the project. Attributes include:

• Stream Type • Stream Features • Bedding Material • Vegetation Type • Stream Name • Stream I.D. • Upstream and Downstream Nodes (InfoNet) • Comments (allows for individual description)


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3.6. Ground Truthing To confirm the accurate location and condition of the streams it was necessary to perform on-site ground-truthing for each potential stream location. This provided a detailed analysis of each stream, and also provided some challenges.

• Weather: Mapping required fine weather, both for site-access and to ensure that stream flows were not affected by rainfall, which would have skewed the findings regarding permanently flowing streams. Fortunately the 2012/2013 Wellington summer was very dry, with only a handful of potential mapping days disrupted by wet weather.

• Access: As a number of these stream sites are within native reserves, the Town Belt or private land, access was an obstacle for accurately ground-truthing estimates.

• Volume of Information: The research process involved ground-truthing a large number of potential stream sites, with only a comparatively small number of actual streams identified. Out of hundreds of sites checked there were 65 streams identified.

• Stream Type Differentiation: The steep topography of Wellington made categorizing streams crucial, as there are a multitude of sites with permanent, low-level seepage, or steady flow during rain events which fall outside the boundaries set for 'unpiped streams' in the scope of this project. Waterways were categorized primarily as: Unpiped Streams, Ephemeral Streams, Seepage or Runoff. Only the Unpiped Streams set is included within the figures provided here.

3.7. Digitise Information Once collected the information was entered digitally into the WCC GIS database under the title Stream Capture Data.mxd. This dataset contains a number of layers covering the location and length of streams, the conditions at each end of the stream, individual stream features and stream attributes. These GIS layers are accessible to various departments and can be edited and updated to include new information through ArcGIS software.

3.8. Response to Data – Diagnose Knowledge Gaps There are areas which, for various reasons, were unable to be accurately mapped within the bounds of this project. Some fell outside the scope of the project boundaries, and others were due to physical obstructions, privacy issues or lack of sufficient data to locate the streams. These areas have been noted within the mapping process. The layer 'Checked Stream Locations' shows the sites which have been checked for streams and do not contain a permanently flowing stream. The condition of the site will be noted in the attribute table for the each location, whether it an ephemeral stream, runoff etc.

3.9. Discussion with Iwi and other Relevant Parties The results of this study have relevance to a diverse range of interests both within and outside of the Wellington Council system. In addition to the management of the waterways themselves, the stream mapping data will be useful for pest control planning, parks and recreation, tracks, WCC rangers, Infonet, engineering and more. Also local Iwi could have a significant interest in the streams data because of the cultural importance of water to Maori.


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4. Outcomes:

4.1. Existing Knowledge confirmed/strengthened

4.1.1. Existing water courses accurately mapped Central Wellington's unpiped streams have been accurately mapped. Streams are limited to permanently flowing, 1st and 2nd-order, which means those flowing directly to the sea and their major direct tributary streams. Each confirmed stream has an attribute table, and the confirmed streams layer can be edited to accommodate new streams information.

4.1.2. Connections with piped network established Connection nodes between unpiped streams and Wellington's underground pipe network are recorded in the attribute information. This assists the Infonet team when working with the stormwater network, helping to locate connection points for Wellington's piped streams.

4.2. New Knowledge Outcomes: Water Courses Mapped

4.2.1. Total Number of Unpiped Streams Confirmed + Mapped: 65 (Fig. 1)

4.2.2. Total Amount (metres) of Unpiped Stream Mapped: 16,695m

4.2.3. Number of Previously Unmapped Streams: 62 Previously unmapped includes all unpiped streams, minus Owhiro, Kumutoto and Houghton Valley streams which were included on a previous GIS map, although their locations have been amended.

4.2.4. Number of Mapped Streams By Location:

• Kelburn + Thorndon: 13 (Fig. 2)

• Aro Valley + Mt Cook: 17 (Fig. 3)

• Newtown + Berhampore: 4 (Fig. 4)

• Owhiro Valley + Brooklyn: 1 (Fig. 5)

• Northland: 5 (Fig. 6)

• Houghton Valley: 10 (Fig. 7)

• Karori: 7 (Fig. 8)

• Miramar Peninsula: 8 (Fig. 9)

4.2.5. Priority areas to be investigated


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Karori has several potential streams in the south-eastern area of the suburb, some of which correspond to WCC walking tracks (FIG. 10). Makara Peak mountain bike park has Karori Stream running through it, which passes outside of the project boundary, but is a confirmed unpiped stream. Kaiwharawhara Stream is well established in the urban environment, but requires an accurate assessment of which areas are piped and unpiped, as well as documentation of its tributaries. Areas through Khandallah and Newlands also have been marked with potential stream locations (Figs. 11 + 12). These areas should be the priorities for completing the central Wellington area before moving on to more remote suburbs.

5. Gaps in Current Knowledge

5.1. Cross disciplinary project Due to the collaborative nature of the GIS system at WCC there are a number of separate data sets relating to the specific streams/waterways information which applies to the project of a particular department. The role of this Stream Capture Project was to integrate and flesh out these datasets into a singular database where all streams data could be stored and easily accessed by all departments.

5.2. Inter-departmental knowledge gaps Because of the fragmentation of data across the system and across various media (GIS, physical maps, first-hand personal knowledge of an area) there were inevitably gaps in the available data. The information relevant to a tracks officer is not always going to overlap with that of an infrastructural technician. The result of this was a series of stream locations with inconsistent data captured.

5.3. Strategy to address gaps One goal of the project was to standardise the information captured for each stream by introducing a series of attribute tables to be filled out for each stream entered into the system. These attributes cover all of the basic data which could be useful to various departments as well as providing a section for entering specific data which may be relevant to a single stream or department. Another way of ensuring the gaps were covered was to employ a variety of sources for data gathering, including many knowledgeable people from outside the council organisation. This information was processed and formed into a map of potential locations for streams before being personally checked through a process of on-site ground-truthing to ensure the accuracy of the data.


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5.4. Clear Methodology for future work Planning

• Establish estimated location of stream

• Research stream context: approximate length, surrounding terrain, private/public land, access etc.

Data Collection

• Take a 'Juno' handheld GPS device - GIS staff can train on how to use these.

• On-site, using the 'capture point' GIS layer mark the end point of the stream.

• Use 'capture line' to collect the centre line as you walk the length of the stream.

• Use 'capture point' to mark any significant features within the stream - tributaries, culverts etc - there are drop-down attribute tables for the most common of these features, and a comments section for others.

• Once the stream data has been collected, save changes to the GIS layer.

Digital Mapping

• Connect the 'Juno' to your computer via USB connection

• Use 'post updates' to apply the most recent updates to your GIS maps.

• Load the Stream Capture Data file in ArcMap

• The stream updates will be located within the layers 'capture point' and 'capture line'

• Edit the 'Confirmed Stream Locations' layer

• Highlight and copy the new stream line

• Right-click and paste the line (this will paste a copy into the Confirmed Stream Locations layer). Make sure that the correct layer is selected to paste into.

• Select the new line and open the attributes table

• Fill in the relevant data fields using the drop-down options or add comments for stream specific data

• Click 'Save Edits'

• Click 'Stop Editing'

• Repeat the process for copying 'Capture Point' data into the 'Stream Features' layer

• Save ArcMap file and close the program. *GIS technicians will be able to assist with this process if there are any difficulties.


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6. Conclusion + Maps

The Stream Capture Project has produced a streamlined and easy to manage database of information regarding the unpiped streams of central Wellington. These digital maps can be accessed, viewed and edited through ArcGIS software. Research into the location of Wellington's streams covered archival, literary and empirical processes, with an emphasis on gathering data from sources within the community when possible. Community groups often have intimate knowledge of their surroundings which can be communicated quickly and effectively to make the research process much more accurate and efficient. Wellington has a large number of community groups working actively within the urban fabric of the city, and engaging with these groups can potentially provide a base for the future progression of the Stream Capture project to Wellington's outer suburbs.


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Figure 1: Wellington's Unpiped Streams


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Figure 2: Kelburn + Thorndon Confirmed Streams

Figure 3: Aro Valley + Mt. Cook Confirmed Streams


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Figure 4: Newtown + Berhampore Confirmed Streams

Figure 5: Owhiro Valley + Brooklyn Confirmed Streams


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Figure 6: Northland Confirmed Streams

Figure 7: Houghton Valley Confirmed Streams


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Figure 8: Karori Confirmed Streams

Figure 9: Miramar Peninsula Confirmed Streams


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Figure 10: Karori Stream Estimates

Figure 11: Newlands Stream Estimates


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Figure 12: Khandallah Stream Estimates


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