Decision Notice - OPW22 0251 [As Published]

Native Foresters

 

3.0 RESULTS - MARINE PLANT IMPACT ASSESSMENT

The vegetation within the works footprint at Catalina Jetty is all within tidally influenced areas
and deemed as marine plants for this survey. The survey area is dominated by introduced
grasses Blue couch (Digitaria didactyla) and Buffalo grass (Stenotaphrum secundatum)
interspersed with a small amount of native Salt couch (Sporobolus virginicus) at the revetment
wall and along the nver bank. Native spurge groundcover (Chamaesyce drummondil) is also
present in high density within the semi-paved access road area. Two Moreton Bay ash
(Corymbia tessellaris) trees with median Diameter at Breast Height (DBH) of 205mm occur
along the southem boundary of Lot 164 (Tree identification numbers 4 & 5, Figure 2), which
will not be impacted from proposed works.

Two large Swamp she oaks (Casuarina glauca), occur at the eastern and westem boundary
of Lot 164 within Apex Park, with their root systems extending into the proposed works area
(Tree identification numbers 3 & 6, Figure 2). The root systems have also been impacted by
erosion exposing some structural roots along the river bank (northem side of trees). The Tree
Protection Zone (TPZ) and/or Structural Root Zone (SRZ) of these trees may be impacted by
proposed works, and arborist assessment may be required to advise on management of these
individuals, especially in relation to potential impacts from cementitious injection grout at the
westem tree (tree number 6). In relation to tree health, it is considered that additional future
works may be required in the adjacent Apex Park to stabilise the structural root zone of these
trees to ensure that they are not undermined, resulting in potential collapse of these trees into
the river.

Within the river bed one small plant of Dugong grass (Halophila ovalis) with 6 leaves occurs
1m north of the eastern revetment wall within approximately 40cm deep water. The remainder
of the river bed area contains bare sand with a small amount of algae growth apparent on
some of the submerged rocks and parts of the wall.

Adjacent to proposed works along the Noosa River, Swamp she oak are growing below the
HAT along the nver bank, with Moreton Bay ash (Corymbia tessellaris) Small-fruited grey gum
(Eucalyptus propinqua), and Fineteaved red gum (Eucalyptus seeana) above the HAT on the
riverbank.

Total impacts to marine plants cover an area of 231.65m? within the survey area. The areas of
permanent disturbance to marine plants associated with revetment wall replacement and
upgrade works include 13.2m? within section 1 (eastem revetment wall), and 9.3m? within
section 2 (westem revetment wall). The areas of temporary disturbance to marine plants
associated with site access and a holding/ storage area for works include 207.5m? within the
southem section of the Lot and part of adjacent Lot 151, as well as to 1.65m? within the nver
bed of section 1 & 2 where construction may temporarily disturb the sandy substrate and
associated marine plants.

The impacts to marine plants are summarised in Tables 1 and 2, and Figure 2.

The location and distribution of marine plants is shown in Figure 3, with further information on
trees present at site detailed in Appendix C.

 

Catalina Jetty, Gympie Terrace, Noosaville — Marine Plant Assessment 9

Document Set ID: 22549959 Page 28 of 38

Version: 4, Version Date: 23/08/2023