Stream ecology
The stream flow observed over the past year has not been markedly different from 1997-1999, though no rushing torrents and very little flood-borne debris have been observed more than about a metre above normal stream height - perhaps because the rainfall in the few rain events observed has been less.
Sewage overflows from manholes along the stream are apparently still common, with one observed in progress, and reports by Reserve users of the associated odours occurring after rain events throughout the past year or two at least. Raw sewage and associated toilet products, both paper and plastic, were observed in the stream and on the boardwalk during and after the recent observed overflow event. The feminine hygiene products and toilet paper are gradually washing away from the Trial Zone, to the Upper Harbour unless caught on islets or tree roots further downstream, or in saltmarsh or on mangroves in the estuary.
The banks in the area closely observed are deeper and steeper than in 1999, often exposing tree roots, some large. The streambed is generally silt-covered. Zones Aa-Ba (further upstream) have not yet been accessed to see if the stream here is still a crystal-clear trickle over sandstone peddles as in 1999, or if sedimentation by eroded silt now extends to this area.
No invertebrates, fish or eels have as yet been observed in the stream.
We can't remember the seasonality of the frequent splashes, bubbles and sightings in 1997-99 of eels and fish in the stream. We do recall that red damselflies were common in summer, that while weeding we often heard the plop of eels breaking the surface of the water, saw them slide beneath the low overhanging banks, and sometimes encountered them with our feet while wading. At that time eight species of native fish were recorded during survey, kokopu were gently netted and observed for a few hours by a group led by Freshwater Native Fish Society members, and sitting still beside the stream on summer evenings was rewarded with the sight of a banded kokopu wiggling gently to hold its position in shallow water mid-stream.
Since that period, the stream has been scoured by presumably increasing amounts of stormwater from continually intensifying residential and road development.
Streamside vegetation
In Zones Ca, Cb, Cc, Da, Db and Ea, the 1997-99 weeding of Tradescantia and Montbretia resulted in dense streamside vegetation along both banks by Haloragis erecta, Carex, ti kouka, kanono, pate, hangehange and ferns to 2mH. Much if not all of this vegetation has been washed away with bank collapses.
Large tree falls near the bank edge have left some banks 2-3mH and impassable without swinging from branch to branch or wading. At some points the absence of somewhere to stand makes weeding difficult if not impossible, and revegetation unlikely unless and until sedimentation built up a new bank.
These tree falls have created some excellent habitat, though dams observed have been incomplete, creating no pools of still or slow-moving water habitat.
Surviving on these banks are large sprawling stands of kiekie, with few tall trees to climb here, unlike the streambanks further upstream. These kiekie do reach and climb tall trees some metres from the water's edge.
The growth of kiekie since 1997-99 is evident by comparison with archive photographs, but especially clear in observations of the narrow timber-edged "streamside weeding paths" along the sandy streambanks on both sides of the stream. the streamside weeding paths were made in 1987-99 by volunteers to limit their own trampling during the large-scale fulltime weeding project. The timber edging is still intact, in some places full of sand and in others empty, except where banks have washed out.
The Kaipatiki streamside weeding path was easily cleared of superficial Tradescantia throughout the that bank, and discovered to be now fully occupied by kiekie, pate and coprosma several metres tall, and ferns, proving both the path design and weeding operation to have been thoroughly successful in streamside revegetation.
We don't recall whether the timber was treated, but it seems likely. Whether chemically or by heat or radiation, and any impact of toxicity, are unknown.
Removal of deep Tradescantia on the Witheford streamside disclosed the weeding path timber edging, and its steps from the Native Plant Trail, still usable, largely empty of vegetation.
The bank beneath has washed out in several areas.
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