Restoration efforts to transform the shallow, weed-infested wetlands at Alligator Creek into vibrant ecosystems have paid off.
Catchment Solutions Mackay
Erosion remediation at Collinsdale
Catchment Solutions is leading the remediation of large-scale erosion at the Collinsdale property located about 30 kilometres north of Rockhampton.
The Collinsdale property is situated in the Garnant locality. This project involves the rehabilitation of large scale gully erosion using earthworks to reshape and fill the erosion scar, with about 20,000m3 of material to be moved and reshaped. Following reshaping, the site will be seeded and mulched to protect the top soil. The site will then be planted by Conservation Volunteers Australia with a mixture of native trees and bushes to enhance re-vegetation of the site.
To protect the site following remediation, fencing of the site and surrounding catchment along Louisa Creek will be undertaken. This fencing will be combined with the installation of off-stream watering points.
On behalf on Catchment Solutions, Neilly Group Engineering has undertaken flood modelling and a detailed design to undertake the remediation of the large-scale gully erosion. The attached video outlines the site planning and monitoring undertaken to obtain relevant government support and approval.
This project has been endorsed by the Reef Trust Technical Working Group (Gully and Stream Bank Erosion Control Program) and approved by the Department of Environment and Energy.
The project will be tendered in May 2019, with the project earthworks expected to begin by August 2019.
This project is funded by the Australia Government through the Reef Trust Program.
Monitoring at the Styx
As it was the highest tide of the year, the team was able to observe the Styx River tidal bore, which reached the monitoring site upstream on Deep Creek, just off the Styx River.
Habitat Importance of Urbanised Estuaries in Central Queensland
Globally, estuarine habitats rank in the most modified of all marine ecosystems, driven primarily by coastal development. The urbanisation and infrastructure associated with population growth concentrate impacts on ecological communities of coastal regions, with anthropogenic advancement constantly recognised in the deterioration of estuarine process zones. Despite this, Queensland’s estuaries provide habitat to a range of species of significant commercial and recreational fisheries value, with many of these species having been documented to utilise highly urbanised marine fish habitats.
In Queensland, urban marine habitats are generally maintained by landholders, local councils and infrastructure management departments. Maintenance works can be routine (e.g. trimming marine plants on access tracks) or as required (e.g. repair of stormwater outlets) and involve varying levels of disturbance. While most maintenance works are required, there are potential risks to fisheries resources and marine plants, particularly when works procedures do not comply with legislative guidelines.
Figure 1. Example of an urban estuarine site showing signs of marine plant vegetation clearing and degradation, with inset of juvenile sea mullet (M. cephalus), barramundi (L. calcarifer) and mangrove jack (L. argentimaculatus) surveyed from the site.
For the purpose of guiding improvements to the management of urban marine fish habitats, Catchment Solutions conducted a 2-year project investigating and comparing the habitat utilisation by fish and crustacean species of urban, peri-urban and non-urban estuarine sites throughout central Queensland. Particular attention was paid to habitat usage of these areas by species of value to commercial and recreational fisheries. The primary objective was to show the critical habitat role that areas thought primarily of as urban ‘drains’ play in providing refuge for juveniles of important species. Furthermore, densities of marine plant vegetation such as mangroves were also surveyed to evaluate the role marine plants play in providing habitat for these species.
These objectives were achieved by carrying out a range of fish community sampling techniques across a number of different urbanised coastal fish habitat sites including tidal creek habitats (lower, mid and upper tidal sites) and supralittoral wetland habitats in the Rockhampton and Gladstone regions. Sampling techniques included a combination of seine netting, fyke netting, cast netting and the use of baited box traps to sample for fish and crustacean species.
In total, 78 species were recorded from 13 sites over five rounds of monitoring, demonstrating the exceptional diversity that can be found at such sites. This comprised 27 species recognised to be of socioeconomic importance to commercial and recreational fisheries. Analyses comparing overall species presence/absence between urban versus non-urban sites showed no significant difference between assemblages, which provides evidence that the highly urbanised sites surveyed are being utilised by identical aquatic assemblages to non-urban sites. Results also showed that for the species of 27 species of socioeconomic importance to commercial and recreational fisheries, the majority of the catch comprised post-larval and juvenile life stages. This highlights the role that coastal estuarine habitats (urban and non-urban) play in providing important nursery grounds to a high number of valuable inshore species, including barramundi, mangrove jack, sea mullet, mud crabs and banana prawns. Peaks in urban habitat utilisation by post-larval and juvenile individuals of species of socioeconomic importance were found between April and September, and numbers were at their lowest between November and December.
Figure 2. Species surveyed during the monitoring (top to bottom, left to right); 1) yellowfin bream (A. australis), 2) giant herring (E. hawaiensis), 3) barramundi (L. calcarifer), 4) Moses perch (L. russelli), 5) endeavour prawns (M. endeavouri), 6) northern whiting (S. sihama), 7) mud crab (S. serrata) and 8) giant queenfish (S. commersonnianus).
Correlations were identified between tidal connection, marine plant composition and the composition of fish/crustacean communities. There was insufficient data to determine whether any of these links were causal, however it is a reasonable assumption that both tidal connection and plant species composition (i.e. mangroves) play a role in the diversity and abundance of fish that utilise urban marine habitats. Review of marine plants surveyed across all sites identified a period of reduced reproductive activity (i.e. flowering and fruiting) between September and October.
Key conclusions from this research suggest that any maintenance works of urban marine habitats in central Queensland should be undertaken late in the dry season. This is to avoid peak periods of utilisation of these habitats by post-larvae and juvenile fish of socioeconomic importance and to avoid peak reproductive periods of marine plants. Where possible, a minimum 2m vegetation strip should be provided along all urban marine habitats to provide refuge habitat for aquatic communities utilising these areas.
It is anticipated that the outcomes of this work will guide future best management practices of urban fish habitats, such as frequency and timings of routine maintenance works adopted by local governments and land holders of the region. The study also provides a framework for similar research into the field of urban marine habitat utilisation and could be replicated to guide appropriate management of urban marine habitats in other regions of Queensland. Building on the dataset would also provide the opportunity to perform more detailed analysis on the causal links between tidal connection, marine plant composition and fish/crustacean diversity and abundance. Knowledge gained through this study could also be built on by investigating the contribution of urban marine habitats to the commercial and recreational catches.
Peacock bass found at Gooseponds wetlands
Peacock bass are a large, predatory freshwater fish species native to South America. The attractive markings, large size and fighting qualities make the species a highly prized sportfish and extremely popular aquarium fish for hobbyist fish-keepers around the world. Despite this, the voracious nature and diet which consists primarily of juvenile fish, make the species a significant threat to fish communities when released outside of their natural range of the greater Amazon basin in South America.
In January 2018, reports circulated of a Mackay angler who had captured a peacock bass below Dumbleton weir in the Pioneer River. The capture represented the first substantiated reports of peacock bass in Australian waters and generated significant public interest and concern. The potential incursion of this species presented a significant threat to fisheries resources in Mackay, with this large predator capable of severely impacting the abundances of native fish communities.
Following the capture, Catchment Solutions were engaged to undertake extensive electrofishing surveys of the capture location and further throughout the Pioneer River to investigate the extent of the incursion of the species. Following the surveys, no peacock bass were detected in the catchment, suggesting numbers of the species were extremely low, if present within the system.
In January 2019, a further two separate captures of peacock bass were reported from the Gooseponds wetlands in the centre of Mackay’s urban area. These captures were also supported by photographic evidence and suggested that higher numbers of the species were prevalent throughout the Pioneer catchment than initially anticipated. Catchment Solutions were again tasked with investigating the captures, and additional electrofishing surveys were undertaken, however this time, focussing efforts throughout the artificial wetland lagoons of the Gooseponds which were not previously surveyed.
Boat-based electrofishing surveys were undertaken throughout the entire Gooseponds wetlands with each of the major lagoons, including all of the channels connecting the lagoons, being extensively electrofished. Unfortunately, two mature male peacock bass measuring 420mm and 395mm were collected during the surveys. These individuals were removed from the Gooseponds for genetic and gut content analysis in order to establish the origin of these fish, and also the feeding behaviours of these fish when unlawfully introduced into tropical Australian waters. It is likely that continued monitoring into the future will be required to ensure any remaining individuals are removed from the system to ensure an outbreak of the species does not arise.
Throughout the surveys, the capture of all additional species was also recorded. A diverse range of native species were captured in high abundances, showing the vital role the Gooseponds play in providing habitat to a range of important species. In total, 77 barramundi were caught throughout the Gooseponds, measuring from 220mm young-of-year recruits right through to large, 920mm mature adult fish. A rock-ramp fishway constructed at the downstream limit of the lowest lagoon provides fantastic access for juvenile barramundi to enter the Gooseponds from the Pioneer River estuary, where the juveniles can utilise the wetlands for refuge, feeding and growth. Many other diadromous, migratory species also utilise the rock-ramp fishway to access the Gooseponds including mangrove jack, sea mullet, giant herring, tarpon, banded scats and snakehead gudgeons.
Unfortunately, relatively high numbers of introduced tilapia were also caught during the monitoring, which have now become well-established in the Gooseponds since being first identified in the system only several years ago. This species is now one of the most prevalent species in the Gooseponds and highlights the speed with which pest fish can establish themselves when allowed to do so. This species is a declared noxious species in Australian waters and as with all pest fish, including peacock bass, if captured must not be released or distributed and must be immediately disposed of upon capture.
Above the introduced pest fish, tilapia, which were caught in the Gooseponds during the monitoring.
Jungle perch stretch their fins in Brendale
Catchment Solutions and Moreton Bay Regional Council have completed a nature like rock ramp fish ladder at Leitch’s Crossing on the South Pine River which allows economically valuable juvenile fish to move freely upstream.
Catchments Solutions fisheries biologist, Matt Moore, said the native fish were really poor swimmers and could only swim fast in small bursts which meant road crossings, causeways, weirs and culverts were major barriers.
The velocity through the pipes, and the drop of downstream at Leitch’s Crossing, prevented critical life-cycle dependant migrations upstream for decades which impacted on native fish populations.
“We’ve opened up breeding habitat for Jungle Perch and Australian Bass, both of which are popular with recreational fishers,” said Matt.
Councillor Mike Charlton said the new fishway, located on the border between Brendale and Albany Creek, was similar to a set of stairs and allowed fish to easily make their way up and down the peak of an existing culvert one step at a time.
More than 400 tonne of rocks, weighing as much as 3.5 tonne each were strategically placed with a large excavator to form a series of pools interspersed with small 70 mm drops.
Catchment Solutions has completed three out of the planned five fish-ways to re-connect fish habitats
fragmented by barriers in South-east Queensland. These five were identified as the most important to need remediation out of 13,797 barriers in the region.
The South Pine River fish ladder is a joint project between Moreton Bay Regional Council and Reef Catchments with co-funding from the Australian Government National Landcare Programme (Target Area Grant). The design and construction of the Fish Ladder on Leitchs Crossing in Brendale was overseen by environmental consultants Catchment Solutions.
Berrys Weir rock ramp fishway on the Bremer River
Background:
Construction of Berrys Weir partial width rock ramp fishway on the Bremer River in Ipswich was completed in October 2016. The fishway was constructed on a large 2.4 m high barrier (Berrys Weir), making this the longest rock ramp fishway in Australia (Figure 1).
Berrys Weir on the Bremer River was constructed in the 1960’s to impound water for power generation, forming a major barrier to fish migration (Figure 2). The weir was constructed in the lower reaches of the Bremer River, impacting crucial life-cycle dependant migrations between downstream estuarine environments and upstream freshwater habitats. The barrier impacted many native species including a number of economically important fish species, such as Australian bass, sea mullet, and long-finned eels. The Bremer River is also home to the endangered Mary River Cod, which have been re-introduced as part of conservation efforts to save their population. Barriers to fish passage are widely known to adversely impact on fish populations, so the re-opening of over 41 kilometres of riverine habitat along the Bremer River is a big step in the right direction for the recovery of this endangered species.
Berrys Weir was highly ranked during a recent fish barrier prioritisation project conducted by Catchment Solutions (Moore, 2016 Greater Brisbane Fish Barrier Prioritisation). The fish barrier prioritisation was funded by the Australian Government’s Target Area funding stream. The sites’ close proximity to estuarine habitats (~3 kilometres), large area of blocked upstream habitat, and large height of the barrier contributed to its high priority ranking. Through this process Berrys Weir was ranked the seventh most important fish barrier in South-East Queensland. In collaboration with Ipswich City Council, Catchment Solutions set about remediating the lack of fish passage through the installation of a fishway.
A partial width rock ramp fishway was chosen as the most appropriate option to improve connectivity along the lower reaches of the Bremer River. Rock ramp fishways are excellent at facilitating fish passage for the whole fish community; including really small bodied fish and economically important juvenile diadromous fish species as well as adults. Rock ramp fishways are also inexpensive and have a natural appearance when compared to their highly engineered smooth sided vertical-slot fishway cousins.
The rock ramp fishway was funded by the Australian Government and Ipswich City Council, with in-kind assistance from Stanwell Power (asset owners).
Partial Width Rock Ramp Fishway Configuration
The partial width rock ramp fishway extends 90 m in length in a zig-zag (dog leg) configuration, and consists of 33 ridges and pools (cells). The fishway was designed to operate at low and medium flows with a slope 1V:27H. Due to the proximity to estuarine habitats, falls (drops) between ridges and pools were set at 75 mm to cater for weaker swimming juvenile diadromous and small bodied species within the system (Figure 3). Fishway pools were approximately 2 -3 m² and ranged between 0.4 – 1 m in depth during low flows. This provided the resting areas and turbulence dissipation juvenile and small bodied species need to negotiate the large fishway. Ridges consisted of 3 slots, with each slot approximately 100- 250 mm wide and 200-400 mm high, allowing the fishway to operate over a range of flow conditions.
From our sampling, it was found that many small bodied and juvenile fish (figures 4 to 7) were able to negotiate the fishway during the low-medium flow conditions, with the median size of all fish captured just 34 mm in length (n=3514).
In high flow situations when the fishway features drown out, the design provides a steady slope of 1V:14H from the weir crest to the downstream bed as well as the 1:27 slope of the low flow path. Although not sampled during high flows, there are reports of large adult fish (e.g. Australian bass and bullrout) migrating in SEQ streams during these conditions. It is not known whether these fish are able to negotiate the 1:14 overall slope, or track the 1:27 slope of the low flow path. However, given that the existing conditions at this site had an overall slope of 1V:9H with a 1 – 1.2 m vertical drop abutting the weir crest, it is anticipated that the fishway has greatly improved fish passage past the weir in high flows.
Construction of the fishway involved a 21 t excavator fitted with a hydraulic rock grab. The grab was used to place the 400 t of large igneous rock between 1 – 2.5 m and weighing up to 5 tonnes into specific positions to from the ridges and side walls. 32 m³ of fibre reinforced concrete was pumped into position to seal fishway pools and set fishway ridge controls to design levels. A 100 mm high concrete nib wall was constructed on top of the existing weir to divert low flows through the fishway.
Fishway Monitoring Results
Fishway trap monitoring was successfully undertaken across five days in mid-December 2016. For the majority of the sampling period low flow conditions were present, on days four and five flows elevated to moderate as a result of local storm inflows. This provided an opportunity to observe fish movement over changing conditions.
Fishway monitoring results demonstrate that the fishway is operating successfully, with 3514 individual fish representing 21 species (19 native and 2 introduced species) sampled. A catch rate of 690.4 fish/day was recorded across the duration of monitoring. Significantly, native fish represented 99.94% of the catch, with only two alien fish representing two species (platy and tilapia) recorded. Hypseleotris species (unable to be positively identified in the field – specimens sent to the Qld Museum for correct identification which revealed both H. galii and H. klunzingeri) were the most abundant species representing 36.1% of the catch, followed by crimson-spotted rainbowfish, empire gudgeon, striped gudgeon and sea mullet with 25.7%, 16.5%, 11.6% and 5.7% respectively.
The smallest fish species recorded successfully ascending the fishway included a 15 mm Hypseleotris species, followed by crimson-spotted rainbowfish, empire gudgeon, flathead gudgeon and striped gudgeon (Figure 8) at 18 mm, 19 mm, 20 mm and 21 mm respectively. The largest fish species recorded included a 550 mm long-fin eel, followed by fork-tailed catfish (Figure 10), yellow-fin bream and bony bream at 350 mm, 254 mm and 254 mm respectively. The median size of all fish captured successfully migrating through the fishway equated to just 34 mm.
Diadromous species represented 32% of the total species captured, and 36% of total individuals. The smallest size diadromous species included; empire gudgeon 19 mm, striped gudgeon 21 mm, Australian bass 30 mm, bullrout 35 mm, sea mullet 38 mm, long-finned eel 70 mm and yellow-fin bream 254 mm (Figure 9). The median size of diadromous species included; empire gudgeon 35 mm, striped gudgeon 35 mm, Australian bass 35 mm, bullrout 54 mm, sea mullet 65 mm, long-finned eel 255 mm and yellow-fin bream 254 mm.
All fish species recorded successfully migrating through the fishway had to negotiate at least 1.5 m/sec through the ridge slot (low flow conditions), with many fish species migrating through minimum velocities up to 2.1 m/sec (moderate flow conditions).
Interestingly the median size of fish increased with the rise in river flow. During low flow conditions experienced between the afternoon of 15th December until mid-day on the 18th, the median size of fish moving through the fishway equated to 33 mm. A storm event on the afternoon of the 18th caused the river to rise rapidly, during this elevated flow period the median size of fish more than tripled to 110 mm. On the recession of this flow event (19th & 20th) smaller fish began to be more prevalent in captures with a median size of 55 mm. While only anecdotal, these results support the theory that larger fish move during elevated river flows, while juvenile and small bodied species migrate across all flow events, with a preference for low and receding flow conditions to undertake movement (Figure 11).
For more information relating to the Berrys Weir fishway or other fishway projects underway in Queensland, please contact Catchment Solutions on (07) 4968 4200.
From little fish big fish grow…
It sounds obvious, but it’s a feat of nature few of us witness – small fish need time, uninterrupted access to our waterways and a whole lot of good quality habitat to become the big catch that sends tingles through an angler’s spine.
In the quiet of the creeks and rivers, if there’s something getting in the way as our juveniles struggle to the next stage of their life, the inevitable result? Far less good sized, healthy fish in our future.
It’s the equivalent of an underwater horror show for keen fishers – the idea that the next generation will have access to a significantly reduced pool of fish stock and diversity. Who wants to sit in a river mouth ten years from now reflecting on the kind of fish you used to be able to catch?
Now is the time to give it some consideration, according to the latest research. A recent report by Queensland based environmental consultants has identified thousands of potential barriers stopping our native fish in their tracks. Both manmade and natural, these barriers are interfering with our native fishes’ ability to manoeuvre through vital water courses to complete their life cycle. It’s a particularly pertinent issue for diadromous (migratory) species who need to transition from salt to freshwater over the years.
We’re talking some big name breeds – depending on your location, barra, mangrove jack, sleepy cod, jungle perch, tarpon, Australian bass, sea mullet, long and short-finned eels to name a few.
Depleting our waterway health also increases the likelihood of a slow invasion by pest fish who are less sensitive than our natives and who thrive in poor conditions – for example the notorious tilapia, cane toad of the water.
The fish barrier report identified 13,000 potential fish barriers in South East Queensland alone, just the tip of the iceberg. Another report in the Mackay Whitsunday region uncovered 3974 potential in-stream barriers.
While it’s not possible to tackle every barrier, these reports also ranked barriers in order of priority, marking out the top trouble spots to focus on. Here, we introduce you to what fish barriers are and why they matter.
Keep an eye out for part two in this series, which will look at the design and construction of fishways and how we can overcome fish barriers moving forward.
What kinds of fish are being held back by fish barriers?
In particular, diadromous (migratory) species which need to transition between waterways, including salt and freshwater, to complete their life cycle. As previously mentioned, that includes key species like barramundi, mangrove jack, sleepy cod, jungle perch, tarpon, Australian bass, sea mullet and long and short-finned eels.
Many of these much-loved fish species require unimpeded access between freshwater and estuarine habitats to maintain sustainable populations.
If we’re talking scientific terms you can break it down again to:
Diadromous – Diadromous fishes are truly migratory species and whose distinctive characteristics
include that they:
Migrate between freshwaters and the sea;
The movement is usually obligatory; and
Migration takes place at fixed seasons or life stages.
There are three distinctions within the diadromous category:
Catadromous – Diadromous fishes that spend most of their lives in fresh water, and
migrate to sea to breed.
Amphidromous – Diadromous fishes in which migration between freshwater and the sea is
not for the purpose of breeding, but occurs at some other stage of the life cycle.
Anadromous – Diadromous fishes that spend most of their lives at sea, and migrate to
freshwater to breed.
Migrations can vary – some are short and confined wholly to freshwater habitats, while other migrations occur across vast distances and between varying habitats, including between freshwater and near-shore marine environments.
Our native fish can’t jump
Forget the famous images of Atlantic salmon leaping upstream in Canada – our juvenile native fish aren’t even remotely in the same boat. Australian native species are easily knocked back by velocity and brought to a halt by even minor barriers. Historically, Australian waterways have been accessible and they rely on a smooth and comfortable passage between salt and freshwater.
Why they need clear passage
Migration is an essential life history adaptation for many native fish species. Migration strategies between key habitats have evolved for a variety of reasons, including for feeding and reproduction purposes, to avoid predators, remove parasites, to utilise nursery areas and maintain genetic diversity.
Exactly what are fish barriers?
Put simply, fish barriers (natural or manmade) are any barrier deemed to prevent, delay or obstruct fish migration.
Natural barriers can include weed chokes, waterfalls, low dissolved oxygen slugs and high water temperature. Manmade barriers however are more common.
Culprits include culverts, pipes, road crossings, weirs, dams, flow gauging structures, bunds (or ponded pastures) and sand dams.
These structures can be built for a variety of purposes like irrigation supply, flow gauging and regulation, urban and industrial development, road crossings or simply urban beautification and recreation facilities.
How do they affect our fish?
Barriers impact fish communities in many ways. Some barriers such as high dams form complete blockages. Other structures like culverts present partial or temporary barriers, restricting fish movement during particular flow events. Even small vertical drops downstream of road crossings and culvert aprons are enough to form barriers for many fish, particularly juvenile and small bodied species.
How can we get past them?
Manmade barriers are a great target for intervention and remediation works like fishways, which are increasingly seen as the way forward to sustain our native stocks into the future – more on this to come in part two!
Information taken from the: Mackay Whitsunday Fish Barrier Prioritisation Report and the Greater Brisbane Urban Fish Barrier Prioritatisation Report. For more information contact Matt Moore, info@catchmentsolutions.com or www.reefcatchments.wpengine.com/cs/resources
This train is a treat
Wetland ‘treatment train’ improves water quality and runoff from agricultural land
Catchment Solutions, in collaboration with Reef Catchments NRM and Mackay cane farmer Shane Cowley have created a treatment train of wetlands to treat poor water quality runoff from adjacent sugar cane farms reaching the Great Barrier Reef (GBR) in the Bakers Creek Catchment, Mackay in central QLD.
Aerial drone footage showing the Treatment Train.
The project took an holistic approach to wetland design, by treating water quality flowing to the GBR while also providing and enhancing habitat for biodiversity.
This was achieved by constructing four water quality treatment chambers – sediment basin, deep water macrophyte zone, detention irrigation re-use chamber and rehabilitating the existing wetland (last chamber). Endemic native vegetation was planted around the wetland, including macrophytes in the deep marsh zone. A rock-ramp fish ladder was also constructed to improve aquatic connectivity between the downstream estuary and the constructed wetland, which provides important habitat for economically important fish species such as barramundi.
The wetland was designed to capture and treat the first flush flow event (30-40 mm) of the wet season (Oct-Dec), prior to discharging into an existing wetland before eventually flowing into Bakers Creek Estuary and the GBR.
The landholder (cane farmer) is able to re-use the water from the third chamber to irrigate his sugar cane crop. Prior to the construction of the upstream treatment chambers, water high in nutrients,herbicides and pesticides flowed straight into the wetland causing fish kills.This water was then pumped right down for irrigation re-use onto adjacent sugar cane. Now, this wetland is managed for biodiversity, with the water treated in upstream chambers and no pumping down of the biodiversity wetland.
Water quality sampling was undertaken during flow events via auto samplers. The results have been significant, delivering both environmental improvement, as well as allowing the cane farmer access to increased irrigation capacity. Fish ladder monitoring and fish community electrofishing have also occurred.
“This extra water means that I can irrigate nearby cane blocks several more times each year and significantly increase their production, as well as improving the water quality for my wetland and the Great Barrier Reef lagoon.”
– Shane Cowley, Cane Farmer, Bakers Creek.
Results (snap shot)
Event 1 (30-40 mm) Dec 2014
NOx-N – 85% reduction
Phosphorus (total and ortho-P) – 50% reduction
Diuron – 59% reduction
Atrazine – 61% reduction
Hexazinone – 55 % reduction
Between last flow event in Feb 2015 to October 2015
86% reduction of N
90% for P
80% for TSS
