Baltic landscape – innovative approaches
towards sustainable forested landscapes
Beaver-made damming constructions
- cost-effective way to accumulate water in
small-scale retention program in Poland?
Author: Patryk Kaczyński
Marja
ReportKolström
No.8 2014
Work Package 5 and 6
Date February 2014
Author: Patryk Kaczyński
Partner organization: Regional Directorate of State Forests in Olsztyn
Photographs: Patryk Kaczyński, Adam Gełdon
Illustrations: Mateusz Grygoruk, Patryk Kaczyński
Corresponding author: patryk.kaczynski@olsztyn.lasy.gov.pl
http://www.baltic-landscape.net
Content
Abstract ........................................................................... 1
Small-scale water retention in the State Forests ............ 1
The purpose of small-scale retention ............................. 2
Planned effects of small-scale retention ........................ 2
Small-scale retention in the Regional Directorate of State Forests in Olsztyn 3
Include beaver pond and its retained water among small-scale retention structures
........................................................................................ 5
Create support fund for the residents of areas threatened by beaver-caused flooding
........................................................................................ 8
Preventative actions with active securing of lands as prevention against beaver
damage. .......................................................................... 9
Some social aspects of the occurrence and activity of beavers in Poland 11
Final conclusions ........................................................... 11
LITERETURE ................................................................... 13
Abstract
Due to the climate change and poor hydrological management, frequent floods and
seasonal water deficiency has been observed in Poland in the past 50 years. To prevent
its negative influence, State Forests of Poland participate in small-scale retention
program, which aims to increase the retention capability of lowlands and prevent floods
and droughts in forest ecosystems. Implementation of this activity by constructing
hydrological objects has been found rather costly.
European beaver population has been increasing in number in a past decades,
causing damages to forest stands and farmlands. Beaver-made ponds which are a result
of its natural activity, could function in similar way as small-scale retention objects. This
study proposes a possible way of achieving goals of retention programme in Sate
Forests, and tries to estimate to what extent beaver management can deliver a potential
solution. This study also illustrates how funds saved as a result of adaptation of beaver
ponds among small-scale retention structures could be directed to those affected by the
negative aspects of beaver activities and prevent from local conflicts escalation. This
study also shows the social and educational role of beaver ponds and also its influence
on increasing biodiversity in surrounding areas. Paper concludes that beaver water
retention role is highly underestimated and proper beaver management could be used
as a tool of sustainable development.
Small-scale water retention in the State Forests
Observations from the last 50 years indicate an increase in the seasonal water
deficiency in the Polish territory and increasingly frequent floods (1983, 2007, 2013). In
many areas, due to global climate changes and mistaken irrigation activities,
unfavourable trends in existing hydrologic conditions and natural environment were
found. Lowering level of underground water, shrinking areas of water reservoirs,
disappearance of mid-forest lakes, drying of the ground and natural humid settlements in
the forests are only few of the examples. Another problem concerning water retention in
Poland is the amount of available retained water per one inhabitant. In this aspect,
Poland ranks fifth from the end in Europe with 1580m3/person/year with the European
average at 4560m3/person/year (Tsznydel M., Tończyk G., 2012). Efforts have been
made since the 1990s to prevent these problems by successfully realising the forest
divisions of individual projects on small-scale retention. (CKPŚ 2009) As of 2009 a
program titled: Increase of retention capability and prevention of flood and drought in
forest ecosystems of the lowlands.
1
The purpose of small-scale retention
The aim of this project is the retention of surface and underground waters in the
areas under State Forest administration, within watersheds of watercourses, with
simultaneous preservation and support of the development of a natural landscape
(CKPŚ 2009).
The basic plan of the project postulates the creation of 3300 small-scale retention
structures. One of their objectives would be the retention of ca. 31 mlnm3 of water. A
decision was made in the project to focus on small retention reservoirs with a capacity of
up to 100 000 m3 of water and a damming of up to 5 m. One of the reasons for this move
is a global tendency to break away from building large water reservoirs which quickly
become shallow and are difficult and costly in maintenance. (Mioduszewski W., 2003.).
The project assumed that high retention capabilities are created especially through the
reconstruction of existing irrigation systems towards the inhibition of water drainage–a
repair of old errors consisting in excessive water drainage. Actions resulting in a delay
and limitation of drainage, e.g. damming up of water in ditches, ponds, waterholes and
similar terrain depressions, from which water was drained through ditches.
Depending on environmental conditions, various methods of water retention are applied:
- increase of use of aquatic resources through adaptation of existing irrigation systems
for retention functions and elimination of their negative influence on the ecosystem,
including the damming up of water in a network of drainage ditches, and locally the
elimination of redundant ditches,
- construction of water reservoirs,
- slowdown of water circulation in watersheds through rapids, artificial rapids, damming
devices on watercourses,
- renaturalisation of swamp areas, i.e. through inhibiting the drainage of surface waters.
Planned effects of small-scale retention
The planned investments, apart from increasing water resources and the level of
underground waters, will be a significant element of protection of natural values of the
forest ecosystem and increase its biodiversity. Indicators of successfully conducted
activities may include:
- a rise of the surface water level,
- a rise of the underground water level,
- a recreation or improvement of the condition of swamp areas,
- a renewal of the peat formation process on the peat bogs,
2
- a positive influence on the species composition of neighbouring forest stands,
improvement of their health and growth,
- restoration of habitat sands the return of plants and animals associated with wetlandsthe maintenance and restoration of biodiversity in the local forest ecosystems.
Also taken into account must be the fact that a successfully implemented small-scale
retention program may result in local floodings of forest stands, meadows and pastures,
making their proper management impossible. Due to the floodings, a local decay of
forest stands and loss of crops may occur (CKPŚ 2009). If such effects do not exceed
reasonable limits and are limited to the State Forest lands, they should be accepted. It is
in fact an inevitable consequence of the fact that small-scale retention is to restore the
natural hydrographic conditions in the scale of the landscape - sometimes it must
therefore reverse the effects of earlier drainage made for the “regulation of hydrologic
conditions”, afforestation or facilitation of management.
Small-scale retention in the Regional Directorate of State Forests in Olsztyn
The small-scale retention program in the Olsztyn RDSF involves 11 forest districts.
They have committed themselves to build, recreate or restore to natural conditions 809
small-scale retention structures in their administrative area. These structures are to
retain over 13 221 000 m3 of water. This equals ca. 16 300 m3 per object on average. In
fact, the range of the retained water at the individual sites is large and ranges from 558
m3 to 300 000 m3 per object (CKPŚ 2009). Compared to the reservoirs created in the
last century in the world, where the capacity of some exceeded 170 km3(!) and the
surfaces reached several thousands of km2 (Lehner, B., 2005), those used throughout
the RDSF in Olsztyn have a small capacity and small impact on a local nature.
The created reservoirs may seem small, but the costs of small-scale retention are
not counted among the lowest. The total cost of construction and adaptation of 809
structures has been planned for PLN 21 382 000. It is easy to calculate that the average
cost per structure is about PLN 26 000. Considering the range of the amount of the
collected water, this value is not accurate. More vivid probably will be the price of
retention of one m3 of water. In the RDSF in Olsztyn this value is about 1.62 PLN/m 3.
The approximate average cost of retention of 1 m3 of water in the scale of our country is
about PLN 5. At the end of June 2013, 387 of the 809 planned structures (47%) were
built in the RDSF in Olsztyn, and the amount of accumulated water is estimated to be 4
800 000 m3 (36%).
The positive effects of water retention are undeniable, but from an economic point of
view, the validity of such expenditures can be called into questioned. Nature on its own
has already developed further more natural way of creating very similar constructions.
Such facilities could easily be found on the areas inhabited by Castor fiber. The beaver
is one of the few species, apart from humans, able to successfully and radically change
the character of entire ecosystems to suit its needs. From an environmental perspective,
3
the presence of beavers in the area brings great benefits in the form of increased
biological diversity of the flooded areas or in an improvement of hydrologic conditions.
However, the matter could look a little different from the human perspective. The
increasing population of this species is populating new areas which often border with
lands used by humans. A conflict between the interests of land owners and beavers
takes place in these areas most frequently (Tornblom J., Angelstam P., 2011). Though if
we look at these problems from a broader perspective, it turns out that many of the
actions undertaken by beavers are very concurrent with the objectives of forest
management policy conducted in the State Forests.
The construction process of human-made retention reservoirs, apart from its positive
impact on the surrounding ecosystems, is unfortunately burdened with a number of
disadvantages and difficulties resulting from their implementation. This process begins
with the examination of the environmental conditions and planning of small-scale
retention structures. This is done mainly through the determination of areas with water
deficiency in the ecosystem and their causes. At this stage it is analyzed whether
retention actions will not adversely affect surrounding areas protected by Nature2000.
Their validity and cost effectiveness are examined in terms of achievable results. The
second step is to obtain the necessary permits, including written agreements with the
authorities responsible for wildlife protection of in the area, water managers in the region
and the local government units depending on the location of the planned structure
(CKPŚ 2009). The third step is to carry out selection procedures for contractors (EU
tender) and the construction of the structure. Due to legal regulations and lengthy
procedures, this stage prolongs the most the duration of the implementation of the
Project. The fourth step is to commission the structure, monitor the technical condition of
the structure and evaluate the efficacy of and compliance with the planned functions.
This process is highly time-consuming and complex. A maze of regulations
governing the obtaining of permits for construction of such a structure is often
disproportionate to the amount of work put into its construction.
In contrast, one can present here the process of building natural small-scale
retention structures - beaver ponds. The beaver does not require a permit, does not care
about administrative boundaries, or coordinate it with anyone regarding the position of
their buildings. A medium-sized demolished dam can be rebuilt by beavers even over a
few nights. The greatest of its assets is the fact that the beaver does not require direct
funding.
A proper beaver population management could be used as a tool to support reaching
goals of a small-scale water retention program in Poland. Beaver not only could speed
up the process significantly, but also affect social attitude to it. A mixture of beaver and
human-made retention constructions would also find more acceptance in the society.
This aim could be achieved in several ways.
4
Include beaver pond and its retained water among small-scale retention
structures
In their character and basic fulfilled functions, beaver ponds resemble small-scale
retention structures. They are, however, not taken into account when calculating the
amount of retained water in a given area. It is difficult to estimate whether the number of
beaver ponds and their capacity is sufficient to be in the range of interest of hydrologists
or the Forest Service. Some authors argue that the activity of beavers is comparable to
all national small retention programs combined (Tsznydel M., Tończyk G., 2012).
In order to estimate the amount of water stored in beaver ponds, estimates were
limited to the boundaries of the Regional Directorate of State Forests in Olsztyn. Data on
beaver population occurring here is selective and estimated therefore the need arose for
the use of more reliable data. According to law, the Regional Directorate for
Environmental Protection is a state administrative body which estimates the damage
caused by beaver activity. The collected data includes: the number of damages, type of
damage, quantification of damage (e.g. number of burrows, flooded area, etc.) and the
amount of compensation paid. After the development of the data obtained from the
RDOŚ it was found that in the region of Warmia and Mazury, which actually coincides
with the area of RDSF in Olsztyn, 1038 cases of beaver damages were examined in the
year 2012. The total of compensation paid is PLN 3 167 364 (at an average price of euro
for the year 2012 being 4.19 = EUR 755 934,13). By comparison, in 2010 the number of
damages was 726 at the value of PLN 1 626 497, and in 2011 the number of damages
was 1053 with the value of compensations at PLN 2 783 925. There is a clear upward
trend. According to data from 2012 the most common type of damage was flooded
grassland. These floodings accounted for 63% of all cases of damage and the amount of
compensation paid for them is PLN 1 943 836 (61%).
The key value helpful in the calculation was surface damage which is the same as
the area flooded by the building of dams by beavers in the surrounding water course.
The total area of flooded grassland was 2254.18 with an average of 3.44 ha, and the
extent of surface damage ranged from 0.18 to 45 ha.
Research findings of M. Grygoruk from the Warsaw University of Life Sciences were
used to estimate the capacity of each beaver pond formed by the flooding of grasslands.
The research hypothesis of his study was the assumption that the amount of water
stored in the pond is a result of the current hydrological situation of the watercourse, and
the volume and surface of the beaver pond, which vary over time, can be presented as
an ordinate of the elevation of the beaver dam and modeled with selected applications of
the geographic information system (Grygoruk M ). Basing in his work on field
measurements, the author created a digital model of the valley of the river Krzemianka
where beavers had built a dam and a beaver pond appeared. Digital model of the pond
shape and elevation helped to determine this pond capacity. Based on the obtained data
set, the relationship between the surface of the water reservoir and its capacity was
determined.
5
Fig. 1 Digital model of river Krzemianka (Grygoruk M., 2008)
Since the area of the Krzemianka river valley has been extensively catalogued, and
the model of the pond made using advanced computer programs - it served me as a
model beaver pond. Using the above-mentioned relationship, I have determined a
function of showing the change in the volume of the tank depending on its surface.
Then, substituting the surface of individual wetlands (beaver damage from the area
of the Warmia and Mazury voivodeship from 2012) to the formula I have determined the
capacity of each flooded area as if it constituted a separate beaver pond. It has been
discovered that the total capacity of wetlands determined in such a way amounts to 12
735 098 m3 of water. This value is very close to that planned to be achieved in the
lowland small-scale retention project in the RDSF in Olsztyn. On this basis one can
conclude that there is a basis for beaver ponds and water stored in them to become of
interest to hydrologists and the Forest Service when planning small-scale retention
structures.
6
Fig. 2. Graph of the relationship between the surface of the beaver pond
and its capacity (Grygoruk M., 2008)
The adopted method was to be used only to determine the order of magnitude of
retained water in beaver ponds in the area of the RDSF in Olsztyn and is not without
errors. It needs to be considered that only 60% of the beaver damage was taken into
account when calculating the total capacity of wetlands. Beaver ponds that do not cause
any damage to the area of RDSF have not been taken into account at all. On the other
hand, not every flooding caused by beaver activity has the exact same structure as the
model beaver pond regarded as a reference.
If we assume that only half of beaver ponds would be suitable for adaptation as
small-scale lowland retention structures, and water stored in them would be included in
the retention balance sheet, we would achieve savings of several million zlotys. As a
result of taking beaver ponds into consideration when calculating accumulated water we
could easily achieve small-scale retention program aims with much lower costs than
planned. Also the number of man-made constructions in the forests will decrease.
7
Create support fund for the residents of areas threatened by beaver-caused
flooding
Payment of compensation is at present the most common form of compensation in
Poland for damage caused by the activities of the European beaver. Most European
countries, including Germany and Sweden have long since moved away from such a
system, introducing in its place preventive solutions, controlled culling or aid funds. The
compensation system may also be an element of fraud, where the remaining of the
status quo and exaggerating the conflict remains in the interest of the victim in order to
receive further financial gain.
The method of calculating compensation is not consistent in our country, and the
difference in the calculation of compensations between the voivodeships appears to be
significant. For example, in 2009 in the voivodeship of Podlasie examined over twice as
many requests for compensation than in the voivodeship of Warmia and Mazury, and the
amount of claims paid in the two regions were very similar (Janiszewski, P., 2012).
Compensations are usually a heavy burden for the budgets of smaller voivodeships,
thereby reducing the funds to carry out other activities in the field of environmental
protection and sometimes causing reluctance of the environmental services themselves.
In opinion of many of the victims, the compensation sums paid do not fully compensate
for the losses, especially for the fishermen (Klosowski J., 2010). Sometimes it is inducing
people to poaching or illegal habitat destruction.
The money saved as a result of adaptation of beaver ponds as small-scale retention
structures could be used to replenish the aid fund, which would be directed to those
affected by the negative activities of beavers. Such fund would be a great tool to help to
manage beaver population. Mainly, it would compensate landowners for excluding from
production the areas flooded by beavers and keep them in an unaltered state. The
scientists’ research shows that 90% of the damage caused by beavers is formed in the
immediate vicinity (up to 10m) of a watercourse (Czech, A., 2007). Creating there
ecotone zones and their exemption from use could prevent most conflicts. After the
beaver population becoming stable in a given area only 3% of the sites would continue
to cause damage (Czech, A., 2010), (Tsznydel M., Tończyk G., 2012). In areas where
beavers have been dwelling for a long time, there is little land available for population
and intensive formation of family colonies, so migrations occur over short distances and
new sites are created in the immediate vicinity of the former ones. Thus, new pools are
not created, but supplied by those already existing in a given area (Janiszewski, P.,
2012).
Removing from or shooting beavers in places of conflict usually brings short-term
effects, as roving specimens finding abandoned and convenient places to live will quickly
settle in them (usually within the following year). The results are new damages in the
same
places.
(Czech,
A.,
2010).
In some cases voivodeship could propose buy off flooded lands (using savings from not
having to pay compensation) or their conversion or redemption for the ones in a larger
distance from the beaver habitats.
8
An interesting phenomenon that could encourage the beavers to cut down more
trees in the area is the dismantling of beaver dams as a precautionary measure against
losses due to flooding. The beaver will instinctively try to repair or rebuild the dam,
cutting down more trees in order to obtain building material. Having suitable access to
materials, beavers can rebuild a medium-sized dam within a few nights. (Janiszewski,
P., 2012). These studies brings us to a conclusion, that in longer time perspective
creating ecotone zones alongside the water streams near grassland or farmlands will
bring more benefits to both beaver population and land owners. These solutions will help
to mitigate conflicts between beaver activities and local society.
Preventative actions with active securing of lands as prevention against
beaver damage
The ideal solution of most of the problems with beavers would be the introduction of
the principle of leaving a natural buffer zone of about 20 - 50 meters by watercourses
and reservoirs, in which there would be no intensive agricultural usage (Czech A., 2010).
This can be done in many ways, such as through the exclusion of land from use,
creation of ecological lands, nature reserves and other forms of protection.
Some consequences of beaver activities can be easily predicted. Newly built roads,
dams and buildings located in river valleys or on their outskirts should be placed on
higher grounds that will not be flooded even if beavers raise the water level. They should
be located on embankments or natural elevations in the area. This solution is very
effective and long-lasting (Czech A., 2010). New investments and structures should be
designed and implemented in such a way as to prevent the possibility of their destruction
by beavers. It is very important because usually costs of prevention are lower than costs
of possible future repair.
You can also actively prevent against colonization new areas by beavers. Preventing
colonization should be used only where engineering beaver activity can endanger
human life or cause major economic damage. Prevention against colonization usually
boils down to a lessening of attractiveness of an environment in which the beavers could
settle and cause potential damage (Czech A., 2010). It is possible to change the species
composition of tree plantings growing on the edges of ditches or ponds –instead of
species favoured by beavers, plant trees and shrubs unattractive to them, such as
conifer, alder, etc.
Securing the culverts potentially exposed to flooding and destruction by beavers is
another example of preventive actions. Properly used procedures and devices often
enable complete and permanent avoidance of significant damage arising from beaver
activities. In many cases, it turns out that they are much more effective and cheaper than
attempts to destroy their dams and other constructions.
9
Fig. 3. Flow pipe inserted into the beaver dam in Spychowo forest district
(Spychowo small-scale retention program documentation.)
In some cases protecting valuable trees with metal nettings is considered a very
efficient way to prevent beaver from settling in the area (Czech A., 2010). Without
building supplies surroundings would be far less attractive for the beavers. In case
beavers have already build up a dam, it was proved that inserting flow pipes in it, is
much more effective way of decreasing water level in the nearby area than dismantling
the dam, which in some cases could be rebuilt overnight (Czech A., 2010).
Educational activities and conflict advisors
The victims` attitude to beaver damage often depends on personal point of view and
knowledge about the beavers. Education of victims often results in the withdrawal of
claims. A rapid response and an expression of real interest in the particular issue have
an essential meaning. Educational activities have a long-term impact on the
management of the beaver population, and they can yield better results than
compensation itself.
10
Money from the fund could also be used for the training of those responsible for the
initial contact with victims of beaver damages or other people interested in beavers and
their activities. Such a person should be trained in the biology and ecology of beavers
and their impact on environment, conducting field work, and should have negotiation and
sociological skills needed to work with the society. They would be responsible for
conducting basic monitoring of the beaver population and its impact on the local
environment, they would be the first person to resolve or examine conflicts and
establishing contact with a victim. This knowledge and the recognition of indigenous
peoples’ rights and the diversification of values related to forests have led to demands
for broader involvement of the affected people in the decision-making regarding in cases
such as beaver management (Raitio K., 2008).
Some social aspects of the occurrence and activity of beavers in Poland
Beavers have been accused of allegedly being one of the causes of the disastrous
effects of the great flood that took place in 2007. Those suggestions do not have a lot in
common with the reality. They were used to cover up years of neglecting committed by
the Polish state in water management and flood prevention. Such presentation of the
matter in the media caused a polarization of views and opinions on the beaver in society,
in contrast to treating this animal as exotic at a time when it was in danger of extinction.
(Dyer R. A., Butler E. B., 2007).
On the contrary beavers can enhance the natural values of many places such as
educational trails or footpaths, which can be successfully established in the vicinity of
beaver locations and are a great place where many occurring natural phenomena can
be described within a small area. They are increasing the attractiveness of habitats and
landscape elements in terms of tourism, where people could feel closeness to the wild
nature. Promotional campaign which would explain how well beavers contribute to the
amount of water stored in forest could not only improve the society attitude to the specie
but also promote pro ecological multifunctional Forest Service forest management.
It has been found that in the conflict areas beavers sometimes tend to cause
reluctance of local society, but that usually depends very much on the personal attitude
to the beaver itself and knowledge about it (Czech A., 2010).
Final conclusions
Beaver management in Poland has been developing over the last century in different
aspects. Numerous times it was found that its proper handling can influence many local
areas of interest such as agriculture or forestry. Small-scale retention program is very
important and valuable issue from the State Forests` of Poland point of view nowadays.
Apart from its positive biological aspects it could be considered as rather costly. Proper
beaver management including participation and cooperation of regional authorities with
11
local society was found to be a very useful tool to mitigate conflicts and combine
interests of all involved parties. Innovative approach to the beaver-made constructions
has showed to be the possible, low-cost solution of increasing forest water capacity.
Beavers also have a significant impact on increasing the biodiversity of plants and
animals appearing in the modified ecosystems as well as increasing the density of
biomass of fauna and flora around them.
Change in the beaver management is a good example where the humanity and its
relationship with the biosphere, has to be changed in fundamental ways if this biosphere
is going to be able to sustain human society in the long-term. What is foreseen, as
argued here, is not some modifications within the current system, but rather a new
economic and ethical system in order to arrive at ‘sustainable development’(Holmgren L.
2008).
12
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