IPC1998-2124
MINIMIZING THE IMPACTS OF PIPELINE DEVELOPMENT
ON NATIVE PRAIRIE ECOSYSTEMS:
A PUBLIC LAND MANAGER’S PERSPECTIVE
Heather S. Gerling
Public Land Management Branch
Alberta Agriculture, Food and Rural Development
200, J.G. O’Donoghue Building
7000-113 Street
Edmonton, Alberta, Canada T6H 5T6
Telephone: (403) 427-4658
Fax: (403) 422-4244
E-mail: [email protected]
Abstract
Native prairie is recognized in Alberta for its significant ecological,
cultural and economic value. Much of the remaining prairie in Alberta
is under public ownership and is managed for multiple uses and values.
This paper illustrates how public land managers and industry cooperate
to minimize disturbance to this valuable resource. The emphasis at the
planning stage is proper inventory and identification of sensitive
landscape, plant and animal features on proposed alignments, followed
by appropriate realignment or mitigative action. At the pre-construction
phase, environmental training of staff has raised awareness about the
value of the prairie resource. During construction, the implementation of
traffic control plans, shut down criteria and innovative soil handling
techniques have reduced the overall impact of activities. Use of special
equipment, erosion control techniques and revegetation strategies during
reclamation can enhance the recovery of prairie disturbances. Proper
monitoring is an important component of successful reclamation, and can
lead to modifications of methods and equipment that give better future
protection to this valuable landscape.
Introduction
The Public Lands Branch of Alberta Agriculture, Food and Rural
Development manages some 1.2 million hectares (three million acres) of
native prairie owned by the Government of Alberta. This land is
managed for multiple uses and values, including: grazing, wildlife
habitat, watersheds and unusual landscapes, recreational, industrial and
commercial activities, conservation of rare and threatened plant and
animal communities and areas of cultural significance. Conserving the
ecological integrity of native prairie ensures that multiple use benefits
can be delivered now and in the future.
There are four types of prairie in Alberta: mixed grass, foothills
fescue, northern fescue and Peace River parkland. The estimated percent
of the original acreage remaining for each type is 24%. 20%, <5% and
<1% respectively. The majority of the remaining acreage is public land,
often because climate, soil or topographic constraints make this land
unsuitable for cultivation.
Continuing threats to native prairie include: fragmentation into
increasingly smaller areas by cultivation and industrial development,
over-grazing, and introduction and expansion of exotic (non-native)
plants. The challenge for the public land manager is to integrate activities
such as pipeline construction without jeopardizing the long-term
integrity of the prairie. The purpose of this paper is to illustrate how
pipeline companies can minimize disturbance to this valuable ecosystem,
and use some innovative techniques to mitigate the impacts.
Regulatory Framework
The objective of conservation and reclamation of disturbed land in
Alberta under the Environmental Protection and Enhancement Act
(EPEA) is to return the land to equivalent capability. This is defined
(EPEA, 1996) as: “the ability of the land to support various land uses
after reclamation is similar to the ability that existed prior to any activity
being conducted on the land, but the ability to support individual land
uses will not necessarily be equal after reclamation.” For larger pipelines,
there is a requirement under EPEA to apply for a Conservation and
Development Approval. This involves the preparation of a
comprehensive report that addresses route selection, environmental
issues, expected impacts and proposed mitigation. Once government
review is complete and concerns have been addressed, an approval is
issued with conditions. On public lands, additional site-specific
conditions may be added as part of the Pipeline Agreement (PLA) that
is issued for any size of pipeline.
There are no laws or regulations that are specific to construction and
reclamation on the prairie in Alberta. However, several government
agencies produced a document in 1992. Petroleum Activity on Native
Prairie: Guidelines for Surface Disturbances, that was well accepted by
industry. The updated document (Alberta Energy and Utilities Board
Copyright © 1998 by ASME
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19%) encourages operators to minimize disturbance to native prairie and
to develop practical methods to mitigate vegetation and topsoil loss or
degradation.
The Prairie Conservation Forum supports this initiative in the
Alberta Prairie Conservation Action Plan (1997). The Forum is a thirty
member organization representing all levels of government, non­
government organizations, industry, academia and agricultural and
environmental interest groups in Alberta. Goal 3 of the 1997 plan (which
runs from 1996-2000) is to: “adopt land use management practices and
protective strategies across the whole prairie landscape that sustain
diverse ecosystems." Reclamation is recognized as an integral part of this
goal: “Reclaim all disturbed sites on native prairie lands with
reconstruction of landscape, soil and native species assemblages.
Encourage the use of native plant species for reclamation or 'cover’
purposes throughout prairie and parkland Alberta."
Planning Phase
The planning phase of a pipeline project is critical for ensuring that
impacts to the prairie are as minimal as possible. Sufficient lead time and
early contact with appropriate regulatory personnel and stakeholders
helps proponents to identify key issues and guides decision making on
routing questions. In Alberta, there is a Land Status Automated System
(LSAS) that contains records of all interests on public land. Companies
are encouraged to consult this information base to determine what parcels
of public land may be particularly sensitive, e.g. legislated “Special
Places”, key wildlife areas, presence of unique features, soil and
topographic constraints, etc. This may lead companies to develop
alternative routes that stakeholders are then invited to comment on.
Public land managers in Alberta encourage proponents to incorporate
pipeline development with existing infrastructure, e.g. access roads.
Inadequate planning of routes was a problem in the past, particularly
with smaller pipelines, with resulting “spider web” developments. Where
large expanses of native prairie are likely to be affected by a major
pipeline development, the formation of an environmental steering
committee for the project can provide a means for discussion and
resolution of issues among various stakeholders.
A comprehensive review of existing information and field
reconnaissance surveys of soils, hydrology, vegetation (including
weeds), wildlife, fisheries, cultural resources and land use are also
necessary during the planning phase. More detailed surveys may be
required when preliminary surveys indicate that significant features will
be impacted by the proposed alignment. An example might be the
requirement for a rare plant survey, following consultation with the
Alberta Natural Heritage Information Centre (ANHIC), discussion with
conservation groups, and reconnaissance surveys that identify
environmentally significant plant communities. Once specifics are
known, mitigation strategies are developed. When a proposed alignment
impacts a significant resource, the first question that should be asked is
whether a re-route is feasible. This has been done on public land in
Alberta where specific or multiple sensitivities exist, e.g. rare plant
communities, rough topography, sensitive sandy soils. In one case the
pipeline was rerouted onto less environmentally sensitive cultivated land.
Minor reroutes have also been done to avoid concentrations of rare plants
or significant archaeological sites.
Mitigation options must be developed to address the environmental
issues that come up on each project. On native prairie, some of these
issues include:
-destruction of valuable native vegetation, including rare plant
species,
-lack of suitable native seed for revegetation,
-difficulty of re-establishing some prairie species,
-introduction of non-native plant species (weeds and persistent
agronomic species),
-damage to vegetation adjacent to the right-of-way due to traffic and
grading operations,
-disturbance of wildlife habitat during construction, particularly rare
species,
-potential for erosion of topsoil,
-potential for damage from grazing livestock during reclamation,
-potential for damage to prairie vegetation and soils due to wet
conditions.
The next sections will describe some of the mitigative actions that
have been developed by proponents, public land managers and other
stakeholders to address these concerns in Alberta.
Pre-Construction Phase
There are two important things that proponents can do to prepare for
the construction phase. One is to hire competent, experienced staff who
are cognizant of the value of the native prairie ecosystem. It is
particularly important to hire environmental inspectors who are aware of
the environmental issues and who will do everything they can to
implement the mitigation measures approved for the project. The second
thing that is particularly valuable for very large projects is environmental
training for staff. On one project in Alberta, this involved a mandatory
training session for all staff involved in construction and reclamation.
Construction staff were taught about the endangered animal species they
might encounter during construction or reclamation and what procedures
to follow. Some companies hire specialists such as wildlife biologists,
botanists or archaeologists for the construction period to handle concerns
that come up.
Construction Phase
There are many things that can be done to reduce the impacts of
pipeline construction on the prairie. Timing of construction and
reclamation activities is important, particularly for affected wildlife
species. Efforts are made to avoid construction during periods that would
negatively affect wildlife species of concern. Public land managers do
not allow construction during the spring breakup period to avoid
excessive damage to vegetation and soils. Companies are also asked to
have clear shut-down directives in place. On public land, shut-down is
required during inclement weather, when rutting starts to significantly
affect the prairie surface. There is also a requirement to clean equipment
prior to entering native prairie areas or watercourses to prevent the
spread of weeds.
One of the most successful mitigation strategies to reduce impacts
to native prairie has been the implementation of traffic control plans.
These plans help to reduce the damage to vegetation on the travel lane,
work-side and access points by reducing the overall number of vehicles
and number of passes by heavy equipment. Multiple passenger vehicles
are used to bring most of the construction personnel into the job site each
day. Inspectors move up and down the construction area on ATV’s.
There are designated turnaround areas for construction vehicles,
alternative access routes, restricted movement and speed limits. In
addition, surface grading of the work side is only done when there is
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rough micro-topography and a safety concern.
Generally, topsoil stripping is employed for pipelines in Alberta. As
well as providing a better growing medium, topsoil also contains native
plant propagules that can assist in revegetation of disturbed areas. On
native prairie, pipeline companies try to keep topsoil stripping to blade
width, or narrower, wherever possible. Public land managers in Alberta
have also reduced the width of pipeline disturbance on smaller diameter
pipelines (less than 30 centimetres or 12 inches) by requiring companies
to employ the “no strip” construction method. This method involves
ditching without topsoil salvage, or salvage of the top 5 cm (2 inches),
the topsoil seedbank, over the trench prior to ditching. Because the “no
strip” technique disturbs a narrower zone of prairie, revegetation occurs
quickly as plant propagules move in from either side. This technique is
also being tried on an experimental basis for pipelines up to a 60 cm (24
inch) diameter. With a larger pipeline, displaced spoil has to be carefully
feathered over undisturbed prairie vegetation. If this material is not too
thick or compacted, the prairie plants grow through. Limitations to the
“no strip” technique include sandy soils where trench subsidence is a
concern, and soils where salty or gravelly horizons need to be kept
separate.
Reclamation Phase
There are a number of things to keep in mind during the clean-up
and reclamation phase that can enhance the recovery of native prairie
following construction. Sod scalping can be minimized through the use
of “prairie protector blades” during clean-up. These blades made of
strong flexible plastic can be attached to either grader blades or backhoe
buckets. Roach height should be minimized as much as possible. The
prairie environment is already droughty; roaches that shed water may be
very difficult to revegetate.
On the prairie, erosion control is high on the reclamation agenda.
Tackifiers are used during construction to stabilize topsoil piles. Straw
crimping is a popular way to provide erosion control on the prairie in
southern Alberta. Public land managers are concerned about weed
introduction from contaminated straw onto prairie areas and request that
companies inspect the fields where the straw is coming from. It is
important to do this during the growing season to get a good idea of what
weeds are present. Some companies use imprinting machinery to create
waffle-like depressions that help to both stabilize the soil and provide a
better micro-environment for seed germination. On steep slopes, e.g.
coulees, or other extremely erosion-prone areas, erosion control blankets
can be used for stabilization. When trees or shrubs are encountered on
sensitive soils, e.g. sandy, brush hogs can be used that leave the roots
intact. Woody material can be chipped and left on the surface to provide
additional erosion control.
Public land managers in Alberta require the use of native plants
(indigenous to the area) for revegetating disturbed prairie areas. When
appropriate plant species are used, it ensures the ecological integrity of
the prairie is conserved. The loss of native plant species has been shown
to threaten the ability of natural ecosystems to function and to be
sustained in the long term. The goal for revegetation is restoration of
ecosystem function and the eventual return of plant community structure.
Revegetated areas must be sustainable and compatible with the
surrounding vegetation and land use. Companies are encouraged to
develop seed mixes for different ecological areas and site types, in
consultation with the public land manager. Information about native
plant communities, individual species and site types in Alberta is
available in a book, “A Guide to Using Native Plants on Disturbed
Lands” (1996).
Site-appropriate native species are in vety short supply, and
expensive. Public land managers are encouraging the use of plant
material whose genetic origin is as close to the disturbance as possible.
Preference is given to native plant material from Canadian or United
States sources from areas with climate and vegetation similar to the area
where the disturbed site is located. If genetically local, or otherwise
suitable material is not available, land managers may request that
disturbed areas be revegetated with plant species that will provide some
erosion control but will not become a permanent part of the ecosystem,
e.g. short-lived annual crops.
Public land managers also require pipeline companies to provide a
seed analysis certificate for seed lots of each native species. This has to
be done prior to mixing. There have been problems with native seed
containing weed species such as downy brome. This annual weed is not
currently designated as a noxious weed, i.e. requiring control in Alberta,
although some municipalities have elevated downy brome to that status.
Other plant species that are prohibited on prairie revegetation projects on
public land include invasive agronomic species such as crested
wheatgrass and smooth brome.
Seeding rates should match revegetation goals. A lower seeding
rate, e.g. 6-8 kg per ha should be used if the goal is to have offsite plants
recolonize the disturbed area. In some cases, it is possible to employ the
“natural recovery" (no seed) option. Natural recovery is considered to be
a viable option when the disturbance is not large, appropriate species for
revegetation are impossible to locate, distance to problem weed sources
are great and grazing around the site is light to moderate (implying that
a seed source is available). The natural recovery option is sometimes
used in combination with straw crimping or light seeding of annual crops
that provide interim erosion control. Annual weeds, if not too
competitive, can also provide erosion control and usually disapppear in
two to three years when surrounded by undisturbed prairie.
Fertilization is not recommended in the majority of cases for
revegetation of native prairie. The addition of nitrogen fertilizer favors
weedy species and slows down successional processes. The addition of
phosphorus to many prairie areas in Alberta is not beneficial because of
the presence of high concentrations of carbonate that tend to make the
phosphorus less available to plants. An exception may be sandy sites,
where phosphorus may assist establishment of native seedlings.
Maintenance and Monitoring Phase
Public land in Alberta is usually under a grazing disposition. This
may require specific management during the establishment period for
native vegetation. It is very important to define areas expected to have
high impact from grazing animals prior to construction. Sometimes it is
possible to change the cattle rotation so that the animals are out of the
field during the vegetation establishment stage. Where this is not
possible, the use of temporary electric fencing in areas of high impact
can be very effective. Ranchers are also asked to move salt and mineral
blocks away from reclamation sites.
Pipelines on public land should be monitored for persistent weeds.
Many companies undertake spraying programs to control these weeds.
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Public land managers prefer the use of spot spraying when feasible, since
most of the herbicides also kill re-establishing native wildflowers.
Mowing is also popular but care has to be taken to mow at a height (15
cm or 6 in) that does not damage emerging native grasses or wildflowers.
Non-persistent annual weeds do not need to be mowed unless there is
concern that they are out-competing desirable native plants.
Vegetation health should be monitored. Soil compaction can
prevent root penetration and has to be corrected. Paratilling, which
causes minimal surface disturbance, can be used to relieve subsurface
compaction down to 40 cm (16 in). Insect infestations have to be
monitored and occasionally treated. Bare spots, often due to seeding
error, may require reseeding.
Public land managers in Alberta encourage monitoring of new
pipeline reclamation techniques. Sometimes academia are involved in the
process; other times consultants are employed to evaluate the relative
success of various treatments. Currently, experimental trials underway
on pipelines on Alberta’s prairie include: evaluation of various native
species and mixes for revegetation; comparison of revegetation success
on stripped (topsoil) and unstripped pipelines of varying size (up to 60
cm or 24 in); sod stripping and replacement on fescue prairie and various
natural recovery (no seed) treatments.
should be reduced from 80% to 60%. When this is implemented, the
cover value will likely include an allowance of 10-15% litter (dead plant
material).
Future Trends
Concern about disturbance to remaining prairie areas will continue
to grow. There will be more pressure to avoid some prairie areas in
Alberta completely, particularly the endangered fescue prairie (where 5%
of the original acreage remains). When particularly sensitive prairie areas
are impacted, operators may have to consider detailed plant and wildlife
inventory and the use of innovative techniques to minimize disturbance
and mitigate impacts. These will increase the cost of construction.
Companies will be required to find more local sources of suitable native
species, as supplies increase. Many pipeline companies are cognizant of
these trends and are participating in research initiatives to address the
challenges, in partnership with government and academia. These
initiatives will ultimately result in better construction and reclamation
and the protection of our valuable prairie resources.
References
Alberta Energy and Utilities Board, 1996. “P etro leu m A c tiv ity on
96-9, Calgary,
Alberta, p. 7.
N ative P rairie: G u idelin es f o r S u rface D istu rb a n ces ", IL
Abandonment and Certification
Pipeline abandonment procedures are currently in the development
phase in Alberta In prairie areas, public land managers would like to see
as many pipelines as possible abandoned in place to prevent further
disturbance to vegetation, soils and wildlife. In the years between
construction and abandonment, areas revegetated with native species
gradually take on the appearance and structure of adjacent undisturbed
areas, as offsite plants recolonize the disturbance. Redisturbing the rightof-way would set the successional clock back to zero.
Under EPEA, operators must obtain a reclamation certificate once
abandonment and final reclamation is complete. Very few reclamation
certificates have been issued for pipelines to date. Reclamation criteria
for wellsites have been in effect since 1994; pipeline reclamation criteria
are currently in development. Both require examination of landscape,
soils and vegetation parameters on the disturbed area, and compare them
to offsite, or to pre-disturbance site information. The wellsite criteria for
native grasslands encourage minimal disturbance; and where disturbance
does occur, topsoil must be salvaged. The draft pipeline criteria will have
to make an allowance for use of the “no strip" option on native prairie.
The wellsite criteria also encourage the use of native species to
revegetate native grassland on public land; and state that it is expected
that native species will not be fertilized unless approval is given.
E n viron m en tal P ro te c tio n a n d E n h an cem en t A c t (E P E A ), Alberta
Conservation and Reclamation Regulation 115/93, Consolidated
October, 1996, Queen’s Printer, Edmonton, Alberta, p. 2.
Gerling, H.S., Willoughby, M.G., Schoepf, A., Tannas, K.E. and
Tannas, C.A., 1996, “A G u id e to U sin g N a tive P la n ts on D is tu r b e d
L ands" . Alberta Agriculture, Food and Rural Development and Alberta
Environmental Protection, ISBN 0-7732-6125-7, various pages.
Gill Environmental Consulting, 1996,
“R eco m m en d a tio n s f o r
C h a n g es to A lb erta s W ellsite R ecla m a tio n C riteria f o r V eg eta tio n on
A report prepared for Public Land
Management Branch, Alberta Agriculture, Food and Rural Development,
P-21.
D r y M ix e d G r a ss P rairie".
Prairie Conservation Forum, 1997, “ A lb e r ta P ra irie C o n serva tio n
Prairie Conservation Forum, Lethbridge,
Alberta, p. 20.
A ction P lan ", Published by the
Vegetation criteria require that the species planted must be
compatible with adjacent or control vegetation or meet reasonable land
management objectives, and that ground cover is 80% of offsite cover.
In practice, 80% has been found to be too high a value for prairie
revegetation. This requirement has resulted in a lot of companies planting
grasses at very heavy rates (25-30 kg/ha or 28-33 lb/ac) to produce a
stand that has 80% ground cover within 14-18 months. A research study
was undertaken on the mixed grass prairie of southern Alberta to
recommend changes to the reclamation criteria that would promote the
establishment of original vegetation structure and diversity (Gill, 1996).
One of the recommendations was that the current cover requirement
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