Waterways and wetlands investigations

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Theodora Douglas
5 years ago
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1 A4! Waterways and wetlands investigations Wader Beach Project: Gross Pollutant Traps Most of the litter at Wader Beach is sourced from uncontained debris in the Bay being deposited on the beach through wind and tidal action. With the prevailing south-westerly winds and clockwise tidal currents in the Bay, Wader Beach's westerly aspect presents a natural litter trap. Apart from direct sources such as litter dropped along the shoreline by visitors to the Bay and jetsam and flotsam from users of the Bay, a considerable amount of litter is washed into the Bay through Storm Water Drains (SWDs) and natural waterways. We investigated the major sources of water flow in Hobsons Bay and how litter generated in Hobsons Bay is contained through the use of Gross Pollutant Traps (GPTs). Of particular concern were the water flows directly to the west of Wader Beach, in particular Kororoit Creek and Paisley-Challis Drain, which both enter the Bay along Wader Beach itself. We also investigated the storm water drainage system within Hobsons Bay. We requested details of the SWDs, GPTs and any supporting maintenance data from HBCC. HBCC provided a map of the GPTs, a copy of the map is at Annex A, no other data were provided. For the purpose of this investigation, the GPTs were numbered from 1 to 24 as shown on the map in Annex A. Note that these numbers are not HBCC designated numbers. Kororoit Creek. Apart for GPS 12 Kororoit Creek is not protected downstream by any GPTs. We explored the creek in canoes at two points above the ford but with limited success because it is heavily overgrown with the common reed, Phragmites australis. We saw very little free debris and concluded that any litter finding its way into the creek was trapped by the reeds and would only be released during heavy rain. Paisley-Challis Drain. The Challis drain is an open floodway running through a light industrial area. There is a high chain fence on both sides of the drain in the industrial area offering a measure of protection from litter. Only small amounts of litter were observed in the drain. However the last 500metres or so are open to litter. The Paisley Drain below Kororoit Creek Road is an open ditch. The drains join at Maddox Road and flow into Kororoit Creek estuary at the western point of Wader Beach. During heavy rains and storms the area between the confluences of the two drains and Wader Beach floods leaving large amounts of litter. We ran nets across the Paisley-Challis drain, near the outfall to capture debris both during ebb and flood tides but caught very little litter, mostly sea grass. Gross Pollutant Traps (GPT). Of the 24 GPTs shown on the map, 8 could not be located, another 3 were sealed Ecosol Filtration Systems which could not be visually examined, 10 were sump systems with one or more traps connected by metal grids with open mesh covers, and 3 were simple screens across the outfall. Findings Our findings would indicate that: 30 April

The GPTs are not being regularly maintained. The design of the GPTs is such that blockages result in trapped litter being liberated into the environment.

be carried into the Bay. Details of our findings are as follows: GPT 1, 2 and 3 (Jawbone Reserve).

They do not flow directly into the Bay but into the Jawbone Reserve lakes. They were visited on 15 March 2016 and again on 1 March 2017. GPT 1.

There is a secondary trap in a large settling pond before finally flowing into the Jawbone Lakes.

2 The GPTs are not being regularly maintained. The design of the GPTs is such that blockages result in trapped litter being liberated into the environment. Many SWD outfalls are not fitted with GPTs Some waterways had GPTs upstream but there were ample opportunities for litter to enter the system downstream and be carried into the Bay. Details of our findings are as follows: GPT 1, 2 and 3 (Jawbone Reserve). These 3 traps are similar in construction and comprise several interconnected traps or sumps covered by open grids allowing access and visual inspection. They do not flow directly into the Bay but into the Jawbone Reserve lakes. They were visited on 15 March 2016 and again on 1 March GPT 1. Only one trap was easily observed as the site was heavily overgrown. There was no sign that it had been maintained between visits. There is a secondary trap in a large settling pond before finally flowing into the Jawbone Lakes. Little trapped litter was observed and the final outfall is partially overgrown. GPT 2. Similar to GPT1 although less overgrown. There were shrubs and other vegetation growing in some of the traps. Litter such as polystyrene pieces, takeaway cups and plastic drinks bottles could be seen in the traps. 30 April

reeds causing the whole SWD to backflow depositing litter all

Litter seen in the trap comprises drink bottles, plastic bags

It was noted on the last visit that some of the

From our observations it would appear that there is no real

be released in heavy flooding with the debris being caught in

3 GPT 3. Initially the outfall to this trap was completely blocked by reeds causing the whole SWD to backflow depositing litter all around the outfall and around each of the feed-in drains all the way back to Kororoit Creek Road. The outfall has since been dug out. Litter seen in the trap comprises drink bottles, plastic bags and golf and tennis balls. It was noted on the last visit that some of the interconnecting grids are blocking up with plastic bags. From our observations it would appear that there is no real protection against backflow and all the trapped litter could be released in heavy flooding with the debris being caught in the Jawbone lakes. On the last visit it was noted that the outfall is beginning to get clogged again and there was a lot of litter in the swale. However, this litter may be remnant debris from the earlier blockage. 30 April

Williamstown High School grounds and comprises a series of

be locally sourced. The drain outfall is tidal.

4 GPT 4. Visited on 1 March 2017, this site is located on Williamstown High School grounds and comprises a series of ponds and a large drain leading onto Jawbone beach. No actual GPT was found. There was a lot of litter in the ponds but this appears to be locally sourced. The drain outfall is tidal. GPT 5 (Williamstown beach). Visited on 1 March There is no obvious GPT at this location but there is a large SWD leading on to the swimming beach. 30 April

GPT 6 (Battery Rd). No GPT observed at this location.

water run off. There was no obvious outfall into the Bay.

Gellibrand Time Ball and comprises a series of closed covers

5 GPT 6 (Battery Rd). No GPT observed at this location. There were a series of bunds, rocks etc to mitigate storm water run off. There was no obvious outfall into the Bay. GPT 7 (Williamstown). This trap is located near the Pt. Gellibrand Time Ball and comprises a series of closed covers which are marked as Ecosol Stormwater System and a drain into the Bay. Because of the closed cover and the tidal action at the outfall no observations about litter could be made. 30 April

GPT 8 (Williamstown). This is located at the bottom of Ferguson St.

The drain runs into the Bay and although tidal, a lot of debris has

This site was visited several times during the year and there was

Located in a new development off Melbourne Rd.

The trap had caught lots of leaves but no litter was observed.

6 GPT 8 (Williamstown). This is located at the bottom of Ferguson St. There is a covered inspection panel but no sign of a trap. The drain runs into the Bay and although tidal, a lot of debris has collected around the outfall. This site was visited several times during the year and there was always litter present. GPT 9 (Newport). Located in a new development off Melbourne Rd. this trap is easily accessible and appears well maintained. The trap had caught lots of leaves but no litter was observed. Apart from acting as a sediment trap it doesn t appear to be in a good place to control debris entering the water system but may be its purpose is purely storm water mitigation. 30 April

Apart from wondering why they are located

7 GPT 10 and GPT 11 (Altona North). These are sealed Ecosol Filtration Systems. Apart from wondering why they are located where they are, we have no further comment. GPT 12 (Outfall to Kororoit Creek). This trap leads into Kororoit Creek along a long open gully. The trap is covered by solid metal plates, which were opened up for us by Andrew Webster HBCC Conservation Ranger. Little debris was observed in the trap. Was this because it is regularly maintained or is there not a lot of litter collected upstream? 30 April

If there were any then they would protect Cherry

parts of the trap comprise gratings with widely

The gaps were so large that large pieces of debris

8 GPT 13 and 14 (Cherry Lake). No traps found at these sites. If there were any then they would protect Cherry Lake, which doesn't have a trap between it and the Bay. GPT 15 (Altona beach). This trap was visited several times during the project. The drain leads onto Altona beach and the visible parts of the trap comprise gratings with widely spaced bars and large gaps between the gratings. The gaps were so large that large pieces of debris were seen passing through it to the beach while it was raining. There was an access plate above the street drain but it was difficult to see how this trap worked or was maintained. 30 April

GPT 16 (Maidstone Street Altona). in this area.

The first time we visited, 29 September 2016, this site it was fairly overgrown and a snake

However, we could observe a nylon net across the outfall which appeared full of plastic

On our second visit, 27 Feb 2017, the site was completely overgrown and the outfall couldn t

There are several drains into Laverton Creek here and lots of litter in the ditches but no

9 GPT 16 (Maidstone Street Altona). in this area. No GPT or sediment ponds were located GPT 17 (Laverton). The first time we visited, 29 September 2016, this site it was fairly overgrown and a snake barred our approach. However, we could observe a nylon net across the outfall which appeared full of plastic bottles etc. On our second visit, 27 Feb 2017, the site was completely overgrown and the outfall couldn t be seen at all. GPT 18 (Laverton). There are several drains into Laverton Creek here and lots of litter in the ditches but no trap found. Work has recently been completed to manage the water flow under the railway bridge but again no traps were sighted. GPT 19 (Skeleton Creek). Visited on 30 Aug 2016 and 27 Feb The trap is located 50m upstream of the outfall which was fairly blocked with vegetation and litter strewn. Not much litter in the trap and it looks like it could be easily released by backflow. 30 April

GPT 20 (Skeleton Creek, Altona Meadows).

However, when first observed on 30 August 2016 there

that the exit grid was completely blocked with

Any subsequent large flow of water will wash the

GPT 21 (Skeleton Creek, Altona Meadows).

10 GPT 20 (Skeleton Creek, Altona Meadows). This is a large trap with easy access for maintenance. However, when first observed on 30 August 2016 there was little litter in the trap but a lot in the swale downstream. On our second visit, 27 February 2017, it was noted that the exit grid was completely blocked with plastic debris creating a virtual dam. Any subsequent large flow of water will wash the debris over the top of the exit grid. GPT 21 (Skeleton Creek, Altona Meadows). A trap and outfall were observed in the area but not confirmed as the site marked on the map as GPT 21. There were several outfalls in this area. 30 April

GPT 22 (Skeleton Creek, Altona Meadows).

As well as gratings inside the sump there is also a nylon

amount was seen in the downstream swale.

This trap comprises a simple nylon net across the outfall.

11 GPT 22 (Skeleton Creek, Altona Meadows). This trap appeared new or recently refurbished. As well as gratings inside the sump there is also a nylon net. Little litter was observed in the trap and a small amount was seen in the downstream swale. GPT 23 (Skeleton Creek, Altona Meadows). This trap comprises a simple nylon net across the outfall. This appeared effective on 30 August 2016 but was full to bursting on 27 February A lot of the trapped litter consisted of plastic drink bottles. There was also a lot of litter trapped in the reeds downstream. 30 April

Heavy rain would cause backflow and there is nothing stopping litter floating over the exit grid.

12 GPT 24 (Skeleton Creek, Altona Meadows). Another variation of a trap was observed. This one consisted of a rigid metal grid across the drain outlet. During the last visit, 27 February 2017, the grid was blocked with trapped debris and lots of litter was present downstream. Heavy rain would cause backflow and there is nothing stopping litter floating over the exit grid. Acknowledgements Assistance with GPT locations was received from Kim Daire, Sustainability Officer (HBCC), Shaun Young, Waste and Litter Community Engagement Officer (HBCC) and Richard Akers from Melbourne Water. Nick Olliff April 2017 References: Water Sensitive Design Engineering Procedure (Stormwater) CSIRO ISBN and ISBN e-pub WSUD Chap 9 Dec 2010 ISBN Living Hobsons Bay : an Integrated Water Management Plan Hobsons Bay Environment Strategy Stormwater Management Plan and Strategy 1999 to be revised 05/06 Melbourne Water Web Site Annexes: A. Map showing location of GPTs in Hobsons Bay 30 April

13 Annex. A: Map of GPTs in Hobsons Bay! 30 April

Philadelphia Creek Trash Assessment (PCTA) Methodology Mill Run Creek Test Case

Philadelphia Creek Trash Assessment (PCTA) Methodology Mill Run Creek Test Case Mill Run Creek emerges from a covered creek in Philadelphia to an open creek in Cheltenham. The Creek has extensive trash