Ludlow River - Ludlow Road North
Basin : Busselton Coast
Catchment : Vasse - Ludlow rivers
River condition at the Ludlow Road North site (site code:VR6LUDL1, site reference: 6100328) on the Ludlow River has been assessed as part of the Healthy Rivers program using standard methods from the South West Index of River Condition (SWIRC). The SWIRC incorporates field and desktop data from the site and from the broader catchment. Field data collected include the following indicators, assessed over about a 100 m length of stream:
- Aquatic biota: fish and crayfish community information (abundance of native and exotic species across size classes, general reproductive and physical condition)
- Water quality: dissolved oxygen, temperature, specific conductivity, and pH (logged in situ every 30 mins over the dry season), as well as laboratory samples for colour, alkalinity, turbidity and nutrients
- Aquatic habitat: e.g. water depth, substrate type, presence of woody debris and detritus, type and cover of macrophytes and draping vegetation
- Physical form: channel morphology, bank slope and shape, bioconnectivity (barriers to migration of aquatic species), erosion and sedimentation
- Fringing zone: width and length of vegetation cover within the river corridor and lands immediately adjacent, structural intactness of riparian and streamside vegetation
- Hydrology: measures of flow (velocity) at representative locations (compared against data from stream gauging stations within the system)
- Local land use: descriptions of local land use types and activities (compared against land use mapping information for the catchment)
The Ludlow Road North site was assessed on 3–4 December 2024 (first known river health assessment of this site). A water quality logger was deployed in October 2024 to assess condition over the 2024-2025 dry season (scheduled to be retrieved in May 2025). The water quality logger enables assessment of water quality in response to changes in climate and streamflow.
Other data:
Another site on the Ludlow River, about 1.2 km upstream of the Ludlow Road North site, was assessed in October 2009, see Ludlow River - Off Tuart Drive - Healthy Rivers
The Ludlow Road North site is about 1.5 km upstream of the Department of Water and Environmental Regulation’s (the department) flow gauging station on the Ludlow River known as Ludlow (site reference: 610009), which has been in operation since 1991.
Search the site code or site reference in the department’s Water Information Reporting (WIR) system to find data for this site and nearby sampling points (flows, surface water quality, groundwater monitoring, department’s meteorological data). See also the Bureau of Meteorology website for additional meteorological data for the area.
Condition summary
The Ludlow River is in the central east of the Geographe catchment and discharges into the Wonnerup Estuary, which is a Ramsar listed site (Wetlands of International Importance). The river has seasonal flow and becomes disconnected over summer. The upper catchment is in the Whicher Ranger National Park, and part of the river flows through the Ludlow Tuart Forest in the lower catchment. The river has cultural significance to the Wardandi people, and registered sites of significance can be found within the catchment.
Land use in the lower catchment (Swan Coastal Plain) is comprised of agriculture and horticulture. Please visit this link for more information on water quality and nutrient concentration and targets for the Ludlow River.
Considerable effort is underway to improve health in the system and wider catchment under the Revitalising Geographe Waterways program, run by the multi-agency Vasse Taskforce. A River Action Plan developed by GeoCatch in 2002 outlines the characteristics, values, condition and management issues of the system. More information can be found here.
The 2024 condition assessment was carried out within the Noongar season of Birak which is considered to be the first summer with rising temperatures and decreasing rainfall.
- Six native fish and crayfish were detected as well as the South West snake necked turtle and the threatened Carter’s freshwater mussel. This meets expectations for aquatic biodiversity for this area. One non-native fish species was found (low abundance) and no other non-native aquatic fauna species were detected.
- Fish populations were healthy with signs of breeding and recruitment in several species. with 70% of the Nannoperca vittata (western pygmy perch) and 50% of the Pseudogobius olorum (blue-spot goby) being juveniles.
- Water quality remained within ranges preferred by local native species, noting that data has only been analysed to early summer. Water quality probes continue to measure conditions through the dry season.
General site observations
The image at the bottom of the page represent condition during the Healthy River assessment.
- The site was disconnected about 30 m downstream of the Ludlow Road North bridge with no clear visible passage between pools.
- There was a small percentage (2% coverage) of emergent and submerged aquatic plants as well as moderate amount of woody debris (small twigs to large logs observed).
- Majority of the site had over-hanging roots and over-hanging banks providing additional habitat.
- Riparian zone was reduced (no shrub layer present), with limited native groundcover, and around 50% cover of remnant trees; providing good shading to only small sections of the site.
- Obvious sedimentation observed, majority of the site banks affected by erosion, with poor to good structural integrity observed in places.
- Much of the assessment site upstream of the bridge was turbid and orange in colour.
- A range of water depths were detected through the site, the deepest section (over 1 m) observed upstream at the logger location, about 40 m upstream of the bridge.
Water quality
A logger was deployed on the 4 October 2024 to monitor water quality over the dry season (October to May). Water quality remained within ranges preferred by native species, noting that data has only been analysed to early summer.
- Water temperature was optimal and did not exceed the upper temperature threshold of 25°C during the logging period.
- Dissolved oxygen was near optimal (>4 mg/L) for the majority of the sampling period, with only short (< 8 hrs) periods of time, being under 4 mg/L.
- Specific conductivity (which can be used as an indicator of salinity) was within the marginal-brackish salinity category and some increase may be expected through the dry season with evaporation and transpiration.
- Nutrients [total nitrogen (0.82 mg/L) and total phosphorous (0.039 mg/L)] did not exceed ANZECC/ARMCANZ 2000 guideline but are considered to be indicative of moderate disturbance based on the SWIRC categories
- Turbidity was in the high SWIRC category (22 NTU’s), and slightly above the ANZECC/ARMCANZ 2000 trigger value.
- The SWIRC categories are based on analysis of departure from natural local conditions across a range of sites across south-west WA within difference land use settings.
See below for data from 4 October to 9 November 2024. The graph will be updated as data becomes available
Fish and crayfish
The species captured at the site are provided in the table below. The table includes a list of all species previously reported in the subcatchment, which provides an indication of species that may occur at the assessment site. As differences in habitat within a subcatchment naturally influence species distributions, and variability in methods between sampling programs can affect the species caught, this list is only indicative.
Native Species found included:
- Bostockia porosa (nightfish)
- Galaxias occidentalis (western minnow)
- Nannoperca vittata (western pygmy perch)
- Pseudogobius olorum (blue-spot goby)
- Cherax quinquecarinatus (gilgie)
- Palaemon australis (south-west glass shrimp)
Non – Native Species found included:
- Gambusia holbrooki (eastern gambusia)
Note: collection of fauna from inland aquatic ecosystems across Western Australia requires a licence from the Department of Primary Industries and Regional Development (DPIRD) and the Department of Biodiversity, Conservation and Attractions (DBCA). All species collected must be reported to these agencies as part of licence conditions.
Species found in subcatchment
Other aquatic fauna
Although not targeted by collection methods, south-western snake-necked turtle and Carter’s freshwater mussel were observed at the Ludlow Road North site.
For more info on aquatic species, please see the River Science fauna page.
References and further reading:
