FORESTRY and WATER QUALITY
Forestry and Water Quality
Road construction, deforestation and/or logging in a watershed may impose a variety of effects on the physical, chemical and biological character of receiving watercourses. When forests are clear felled or selectively logged, significant areas of surficial soils and sediments may be exposed to rainfall-based erosion and scour. Surface runoff to drainage lines may contain elevated concentrations of fine sediments, coarse and fine particulate organic matter, and nutrients.
Predictions can be made of the magnitude, frequency and duration of suspended sediment concentrations in receiving waters, based on sediment transport capacity calculations at different flow regimes. Reasonable forward estimates can be made of the transport and deposition of sediment in streams draining watersheds having forestry operations. These data can be used in a probabilistic assessment of water quality and aquatic biological impact.
Sources of Sediment
Sediments sources from forestry operations and entering receiving waters have direct and indirect
sources, such as:
- Deforestation and logging per se.
- Surficial soil erosion from extraction tracks, road construction, and other infrastructure areas.
- Streams intercepted directly by operations.
The following analyses can be performed by analytical laboratories subcontracted by EnviroGulf Consulting or measured in the field:
- Turbidity by turbidometer or Secchi disc.
- Sediment physical and chemical properties:
- particle size grading
- multiscan elemental analysis
- nutrient status
- cation exchange capacity (CEC), pH, Eh, carbonate content, carbon content, etc.
- Receiving water quality:
- general water quality (DO, temperature, TOC, DOC, conductivity, alkalinity, etc).
- nutrients (total phosphorus, soluble phosphorus, nitrate nitrogen, total nitrogen).
- suspended sediments, coarse particulate organic matter (CPOM), fine particulate organic matter (FPOM).
EnviroGulf Consulting offers clients a consulting service centred on impact assessment of the effects of forestry operations on receiving water ecosystems.
The assessment of the effects of forestry developments and operations in mobilising sediments to receiving waters is complex. EnviroGulf Consulting uses a multidisciplinary approach using soil engineers and hydrologists where basic data is lacking. Otherwise relevant data is abstracted from Water Commission databases for the watershed under consideration.
EnviroGulf Consulting offers the following services to clients:
- Flow duration analysis.
- Sediment rating curves.
- Sediment transport capacity.
- Prediction of total suspended sediment (TSS) concentrations in receiving waters:
- background SS
- forestry-imposed SS increment
- total SS
- Environmental impact assessment of roading, logging and burning on receiving water quality.
- Prediction of physical effects of sedimentation and suspended sediments on aquatic organisms and populations of rivers, lakes and coastal lagoons:
- algae and macrophytes
- Prediction of sediment impacts on aquatic resource use:
- floodplain plants and crops
- subsistence, artisanal and commercial fisheries
- drinking water quality
- Assessment of aquatic biological impact of changes in stream flows attributable to forestry operations.
- Field surveys:
- water sampling
- sediment sampling
- biological sampling
- Design, planning and execution of water quality sampling and monitoring programs:
- compliance monitoring
- baseline monitoring
- problem-orientated monitoring
- Collation, reduction, statistical analysis and interpretation of monitoring data.
The Principal of EnviroGulf Consulting has carried out numerous sediment impact assessments and evaluations, mainly in the field of mining [see Mining and Sediments]. The following are forestry-related experience:
- Queanbeyan and Badja Management Areas Environmental Impact Statement (1994) - Preparation of an EIS for proposed forestry operations in Queanbeyan and Badja Management Areas, southeast New South Wales (to State Forests of New South Wales).
- Eden Management Area Environmental Impact Statement (1994) - Revision of draft Environmental Impact Statement (EIS) and preparation of a new EIS for forestry operations proposed in Eden Management Area, southeast New South Wales (to Margules Groome & Pöyry Pty. Ltd. for State Forests of New South Wales).
- Grafton Environmental Impact Statement (1994) - Assessment of aquatic environmental effects of road construction and timber harvesting in the Grafton Forest District of northern New South Wales (to Margules Groome & Pöyry Pty. Ltd for Forestry Commission of New South Wales).
- Casino Environmental Impact Statement (1994) - Assessment of aquatic environmental effects of road construction and timber harvesting in the Casino and Murwillumbah Forest Districts of northern New South Wales (to Margules Groome & Pöyry Pty. Ltd for Forestry Commission of New South Wales).
- Boral (SEPL) Environmental Impact Statement (1993) - Assessment of aquatic environmental effects of timber harvesting in the coastal region of northern New South Wales by Sawmillers Exports Pty. Ltd. (SEPL) ( to Margules Groome & Pöyry Pty. Ltd. for BORAL Timber Division).
- See Principal's CV for others.