Orwell Stream assessment
Summary of report findings
Orwell Stream catchment has only recently started to be developed from rural to residential land use. The predominantly rural land use is expected to change to predominantly residential over the next 50 years.
Documents
Orwell Stream report PDF 
(794KB)
Orwell Stream maps (PDFs)
Links
North Shore stream assessments overview page
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| Length |
3.3km |
|
| Size Of Catchment | 170ha | |
| Vegetation Cover | 32% (53ha), generally in the southern part of the catchment | |
| Imperviousness | 7% | |
| District Plan Land Use | Recreation | 16% |
| Residential | 3% | |
| Road | 9% | |
| Special Purpose | 72% | |
| Recreational Use | High, known high public use of stream locality. | |
| Receiving Environment | Te Wharau Creek then to Lucas Creek | |
| Substrate | Predominantly silt/mud | |
| Natural Wetlands | Nil | |
| Artificial Wetlands | 1 | |
| Periphyton | Excessive growth in Tributaries 2 + 5 | |
| Macrophytes | Only one tributary with possible management issues | |
| Macroinvertebrates | Moderate taxa richness | |
| Fish | 7 species of native fish + koura | |
| Potential Man-Made Barriers to Fish Passage to Upstream Habitat | 1 (+ 3 natural barriers). | |
| Channel Modification | Majority of the stream network is unmodified, piped sections only in the lower main channel and in two of the tributaries. | |
| Erosion around Structures | 1 structure with severe erosion + 2 structures with slight erosion. | |
| Bank Erosion | Moderate erosion with sections of severe erosion in the main channel, slight-moderate erosion within the remainder of the stream system. | |
| Temperature |
No data |
|
| Suspended Solids, Turbidity And Visual Clarity | Clarity 0.5 - 0.68m, average 0.56m | |
| Oxygen and Oxygen Demand | No data | |
| Nutrients | No data | |
| Contaminants | No data | |
| Bacteria and Pathogens | No data | |
| Sediment Quality |
No data |
|
| Debris | Significant debris at the lower end of the main channel due to collapse of the banks and riparian vegetation. | |
| Stream Grouping | Group 2, High value low disturbance | 32% |
| Group 3a, Urban semi-modified | 53% | |
| Group 3b, Urban modified | - | |
| Group 4, Concrete lined channel | - | |
| Group 5, Piped section | 15% | |