Water and Soil - Project Planning and Management for Ecological Restoration - page 97

Box 7-1. Lesson Learned: Be Sure Substitute Equipment Is Truly Equivalent
Land imprinting is a technique of using a device that leaves small catchments of a
specific configuration designed to concentrate water, seed, and micronutrients. Used
primarily on lands that are flat to rolling hills with limited water, these devices can be
used on slopes up to 2:1. The senior author, initially not familiar with the intricacies
of the land imprinting process, was persuaded by engineers into allowing the use of a
swamp cat treaded bulldozer instead of an actual imprinter. Although the individual
imprints approximated the imprinting device, there was no system of concentrating
water into small reservoirs at the ends of the track troughs. Instead, the water built up
and eroded the small wall of the trough, and numerous erosion rills were formed.
In another example, the senior author was challenged with the moving of mature
trees. Superiors determined it was not necessary to use a standard tree spade so the
contractor used a standard backhoe. The failure was almost immediate due to an in-
adequate rootball and a major disruption of the rootball by the backhoe bucket.
Lesson learned: The application of equipment designed for one purpose may not
translate completely to the needs of your restoration project. Substitutions to planned
work are not uncommon. When introducing a new technique or piece of equipment,
be completely familiar with its details and how it separates itself from similar equip-
ment or techniques. When a change is proposed, discuss the proposal with your team
for careful evaluation before approving the change.
lation of many projects can be timed to take advantage of a predictable weather pattern and avoid
the need to provide an elaborate system to deliver water to the site. Evaluate the size of the project
and the duration of the “wet” season. In situations with unpredictable or unstable weather patterns,
the use of seeds may be the best choice and plant mortality should be expected at higher levels
than with supplemental watering. This is acceptable as long as you have planned for this approach.
Knowing the growth characteristics of the species will greatly assist in your decisions. Root growth
behavior is an extremely important trait when relying on natural systems. Your design and timing
should account for soil moisture in the root zone during the growing season. Arid lands rely on storm
events to recharge the soil column. To enhance germination results, an imprinting device is used
to create numerous surface depressions. These depressions concentrate water, keep seeds on-site,
and collect debris and micronutrients. Erosion within the depressions buries the seed and reduces
loss by wind and seed-eating animals (Bainbridge 2007). Survival of germinating plants within these
depressions is higher than in adjacent areas. The imprinter is effective on slopes to reduce erosion,
contain seed on the slope, and promote plant growth. Imprinters are designed for the function they
will provide, so a wide range of catchments and water collection systems can be devised. Figure 7.1
shows a small imprinter designed for tight-access slopes. Several attempts have been made to use
standard caterpillar tread tracks to substitute for an imprinter, but with unsuccessful results (box 7-1).
In addition to creating small water collecting depressions, other options are available to concentrate