Table 6.
A description of the potential impacts resulting from bottom-mounted tidal turbine projects. See text, Section 3.3, for a narrative summary of this development scenario. Ecosystem components are ranked by their proportion of the major impacts. Moderate impacts are listed in the order they appear in the renewable energy impact matrix.
| (i4) Bottom-mounted tidal turbine projects | ||
|---|---|---|
| Priority | Major impacts | Certainty |
|
| ||
| (1) Benthic habitat and resources | (i) Changes in hydrodynamics (ii) Scour and/or deposition |
(i) Medium (ii) High |
| (2) Fish species and fishing activity* | Loss of access to grounds during construction and operation (mobile gear) | High |
| (3) Marine mammals and sea turtles* | Noise from pile driving | Medium |
|
| ||
| Component | Moderate impacts | Certainty |
|
| ||
| Benthic habitat and resources | (i) Resuspension of pollutants in sediments | (i) Low |
| (ii) Disturbance from installation/removal of device (turbidity) | (ii) High | |
| (iii) Chemical spills, discharge | (iii) Medium | |
| (iv) Disturbance from installation of cable | (iv) Medium | |
| (v) Changes to current/wave regime | (v) Medium | |
|
| ||
| Fish species and fishing activity | (i) Collision/blade strike | (i) Medium |
| (ii) Pressure gradients around rotor | (ii) Medium | |
| (iii) Chemical spills | (iii) Medium | |
| (iv) Operational noise | (iv) Medium | |
| (v) Noise from pre-construction seismic surveys | (v) Medium | |
| (vi) Noise from pile driving | (vi) Medium | |
| (vii) Noise from pile cutting during device removal | (vii) Medium | |
| (viii) EMF | (viii) Low | |
| (ix) Habitat/community composition alteration | (ix) Medium | |
| (x) Decreased catchability during construction and operation | (x) Medium | |
| (xi) Loss of access to grounds during construction and operation (fixed gear and recreational) | (xi) High | |
| (xii) Changes in species distribution | (xii) Low | |
| (xiii) Damaged/lost gear | (xiii) High | |
|
| ||
| Avian species | (i) Collision with rotating turbine blades | (i) Medium |
| (ii) Pressure gradients around rotor | (ii) Medium | |
| (iii) Leakage of lubricants/fluids, release of maintenance chemicals | (iii) Medium | |
| (iv) Large chemical spills | (iv) High | |
|
| ||
| Marine mammals and sea turtles | (i) Entanglement with mooring lines or cables | (i) Medium |
| (ii) Strikes with installation or support vessels | (ii) High | |
| (iii) Operational noise | (iii) Medium | |
| (iv) Noise from pile cutting during device removal | (iv) High | |
*Denotes that higher priority may be given to this component due to national/regional/local regulatory objectives and obligation.