Restoration Techniques: Site Preparation Overview

Restoration Techniques: Site Preparation

• Site preparation depends on previous land use and functions
• It involves recontouring, structure forming, or grading prior to vegetation application
• Careful soil handling is required for successful ecosystem development
• Site preparation lays the foundation for successful ecosystem development

Landscape and Surface Expression

• Defining visible features of a land area is a crucial goal
• Goals include recreating pre-disturbance landforms, matching local drainage, and preparing for planned land use
• Reclamation criteria assess the site holistically from various vantage points, comparing it to adjacent land
• Drainage operability and contour are considered aspects of successful landscape development

Landscape and Surface Expression (Continued)

• Reclamation criteria involve qualitative evaluations (e.g., forested and grassland)
• Drainage patterns and capacity are assessed
• Erosion signs (wind or water) are evaluated
• Slope stability issues like movement, subsidence, and tension cracks are noted
• Bare areas should match surrounding communities
• Contours and intended land uses are compatible
• Industrial debris is not present

Landscape and Surface Expression (Continued 2)

• Landform features influence plant establishment
• Crucial features include slope, aspect, shape, stability, and soil texture
• Natural site restoration focuses on small-scale modifications
• Uniform areas are preferred, and traditional reclamation leads to simplified contours and filling of features

Landscape and Surface Expression (Continued 3)

• Natural sites have varied soils, leading to greater plant species diversity
• Graphs display topsoil depth vs. grass and forb percentages and cover rates.

Modification of Surface Features

• Landform reconstruction shows heterogeneity of materials and mesotopography
• This relates to oil sands mining rehabilitation in Alberta, Canada

Landscape and Surface Expression (Continued 4)

• Increasing surface structure enhances wildlife habitat
• Important features include escape terrain, nesting sites, burrowing sites, and cover from climatic extremes

Landscape and Surface Expression (Continued 5)

• Site stability is a concern, especially with compaction
• Issues may include compaction from roads, access points, and storage areas
• Compaction depths vary based on grassland or forest soil types, affecting freeze-thaw cycles and root zone depth
• Alleviating compaction requires addressing potential problems, like impenetrable layers and nutrient and water movement restrictions

Alleviating Compaction- Shallow

• Microsite focus enhances native plant germination
• Techniques include chisel plows, curved shanks, disk plows, and field cultivators, affecting soil depth (5-10cm)
• The shallower methods aim to hold topsoil for germination

Alleviating Compaction- Deep

• Deep methods use winged subsoilers, rippers, and excavators to improve soil structure
• Commonly used in frozen or dry but not saturated boreal sites with high organic content

Modification of Surface Features (Continued)

• Surface roughness modification increases site diversity and manipulates topsoil, overburden, and debris
• Resulting benefits include increased habitat diversity and reduced runoff
• Methods include adding above-grade features and below-grade features
• Above-ground features reduce wind and water flow, improve nutrient and organic matter retention, and support plant growth
• Examples include free dumping overburden, track packing, and mounded pits and adds

Modification of Surface Features (Continued 2)

• Below-ground additions like depressions accumulate water, nutrients, and organics
• Utilizing natural disturbance features is an option
• Inversions in mounds, either above or below grade can be part of creating "rough and loose" textures and topography

Modification of Surface Features (Continued 3)

• Excavation techniques create above and below-grade features, like mounds and pits
• Techniques like mounding are frequently observed on peatland and forested sites

Topsoil Replacement

• Ideal topsoil is the growing medium and living soil
• Salvage of original topsoil is preferable
• Matching topsoil thickness to site requirements is essential, especially for original and off-site comparison
• Moisture content should be less than 75% field capacity

Topsoil Characteristics

• Crucial considerations in topsoil replacement include salvage depth, salvage time, stockpiling duration, placement depth, amendments, and placement shapes

Placement -islands

• Maximizing surface area promotes native species egress
• Initial two years focus on grass and forb seed dispersal
• Vegetative expansion is slow

Topsoil Concerns

• Placement considerations influence deed bank quality, soil characteristics, salvage depth, stockpile characteristics, placement depth, and placement location

Topsoil Replacement (Continued)

• Peatland soil restoration prioritizes hydrologic connectivity
• Challenges arise due to external material and compaction in peatland environments
• Peatlands often require incorporating air and pore space
• This can be done using techniques such as partial pad inversion or complete pad inversion

Method 1: Removal and Re-Exposure

• This involves removing the complete clay pad, geotextile, and promoting hydrological functionality using a fluffing technique to restore volume
• Stopping the procedure in areas with insufficient peat and using alternative techniques for varying locations for optimal results is essential

Complete Peat Inversion

• The invert method overturns the clay pad and underlying layers in a process that resets and isolates the clay/mineral surface from the peat
• Removal of the underlying peat is a crucial step, allowing further action

Method 3: Partial Pad Removal + Inversion (aka Mineral Initiation)

• This method involves partial and complete clay pad removal in one portion, then reconfiguring layers of existing material
• This process entails moving native materials and geotextile, then placing the remaining layers on top
• The outcome ensures both hydrology function and biodiversity

Stability Issues

• Ensuring landscape stability involves managing erosion and sedimentation
• Methods like increasing surface heterogeneity through mounds and shelves, along with cover crops or bioengineering techniques, are beneficial

Bank Stability and Waterbodies

• Understanding waterbody use and risk factors is crucial to stability concerns
• Flow rate changes and land use modifications are important factors
• Solutions often involve filtration systems, vegetation, structure, and effective mitigation measures

Bioengineering

• Bioengineering techniques for slope stabilization include riprap (various sizes of stones placed, which limits erosion) and other approaches
• This can involve staking riprap to halt erosion
• Sometimes, bank extensions may be needed to halt erosion and sedimentation
• Deterring use, either for wildlife, or human access, reduces disturbance to the landscape

Examples of Slope Stabilization with Bioengineering

• Gabion cages, rock-shaped fences with rocks inside are used for vegetation growth
• These are examples of slope stabilization with bioengineering techniques

Examples of Slope Stabilization (Continued)

• Alternative design treatments for slope toes may use logs, riprap, rootwads, or geobags

Site Preparation Timing

• Site preparation needs to be carefully timed to have success as early efforts may be repeated if too early
• Site preparation is often dependent on scale, access, challenges, and overwinter considerations
• The timing of the preparation must consider the vegetation planting schedule, freeze-thaw cycles, and any lingering compaction issues

Summary

• Effective site preparation is vital for a thriving ecosystem
• Key aspects include stability, topsoil addition and vegetation selection that ensures a healthy growing environment
• Consideration of water retention is also crucial.

Explore the essential techniques of site preparation fundamental for successful ecosystem development. This quiz covers aspects such as recontouring, drainage, and the importance of reclaiming visible features of land. Understand the criteria used for assessing land usability and how careful soil handling contributes to restoration.