Pump Station Screening Project
Pump Screening Solutions for TNIS Pumps and the Environment
The modernisation Continues
In August 2019, a seminar was held by the NSW DPI Fisheries and AWMA Water Control Solutions at the Trangie Golf Club. It highlighted the benefits of screening pump intakes for both the environment and the local irrigators.
Trangie Nevertire Irrigation Scheme (TNIS) expressed an interest and showed their pumping infrastructure to DPI Fisheries and AWMA. They were impressed by the TNIS pump site and interested in using it for a trial, to fit Fish Exclusion Screens.
A screening solution was designed and then fitted to the TNIS pump station in July 2020.
The cone screens that were selected were designed for shallow water & partially submerged with silty conditions. They meet NSW Fisheries guidelines to protect fish from entrainment or impingement, along with protecting pumps from clogging with debris. The aim was also to lower running costs by reducing power demand charges and increasing pump efficiency.
The screens have low maintenance requirements and costs. Being constructed from 304 stainless steel wedge wire, they are strong and hopefully have a long asset life.
There are three cleaning brush arms located on each cone. They are automated to clean in the event of head loss, through the screens or once a day minimum for one minute each. (A total of four minutes a day.)
The advantages of selecting cone screens is they have a positive brushing action, preventing debris build up, sedimentation and bio-fouling. Moreover, they can be used even if not fully submerged, having a large surface area with a smaller footprint.
How do pump screens work?
The primary way the fish screens do this is by reducing approach and through slot velocities. For example, a normal pump inlet could have an inlet velocity up to and possibly over 3m/second. This means the “area of influence’ around the pump inlet is significant. It can drag a lot of debris to the pump from a long way away.
The cone screens have an approach velocity of only 0.12m/second, at a flow capacity of 600ML/day – and much less at lower pumping volumes.
By pumping less debris at the pump station, TNIS hope that its members will be seeing a reduced debris amount being delivered on-farm. This will also hopefully reduce on-farm running cost.
Most TNIS members now use Lateral Move or Pivot Irrigator systems. They use sprinkler nozzles that are prone to blocking with debris.
Another advantage is hopefully for the environment! By not pumping debris, egg larval and even adult fish, we here at TNIS hope it’s a win-win situation for our members, the NSW Rec Fishers – and the fish.
NSW DPI Fisheries have a team of Researchers that will be conducting controlled tests throughout the 2020/21 TNIS pumping season. They will be checking the channel system for egg larval, fish and the screens effectiveness.
They are hoping these screens will save many native fish each year from irrigation pumps. Furthermore, if it can be proven that the screens work, TNIS hope it may help free up more funding and allow other irrigators to have screens fitted in a similar fashion.
This screening project is in conjunction with NSW DPI Fisheries, NSW Department of Planning, Industry and Environment, Energy and Science (NSW DPIE EES who were previously the Office of Environment and Heritage (OEH)).
The work itself was funded by money generated by the sale of environmental water in 2018. It is now being invested back into fish friendly infrastructure through the NSW Drought Relief Initiative.