The
need for a better water management and new solutions to the impacts of climate
change and population growing is an imperative in today´s world agenda. Deterioration
of ecosystems and natural areas has led to loss of biodiversity, droughts, floods,
spread of diseases, damages in agriculture, unequal distribution of wealth and
many other social, economic and ecological negative impacts on the rural and
urban peoples all over the world. In consequence, the Ecosystem Services (ES) approach
emerged to consider the ecosystems as the base on which all kind of development
must be sustained and to deal with these conflicts comprehending the complex
link between humans and environment [1]. Furthermore, ES concept involves not
only natural cycles (chemical elements, water and physical ones) but also their
interaction with human activities (micro and macro economy, governance, culture,
power relationships, etc.). Later publications have extensively gone deeper on
the new ways to perceive and solve water, habitat and food problems related to
ecosystems [2-4].
Considering
this, in the cities of Leon in Nicaragua and Darmstadt in Germany, these
impacts are observed at different scales and magnitudes due to the interactions
between river ecosystems and surrounding areas involving human development as
background. In this regards, several studies and researches have been developed
to understand the state of the art on the hydrological, ecological, and
potentiality of ES provision as well as the driving factors of ecosystem
alteration in both areas, and in turn provide technical base for decision
makers with the aim to reach a sustainable solution for different problems such
as: water quality, extreme decrease of flow, loss of biodiversity, etc. [5-11].
All in all, the Nature based Solutions (NbS) framework through the Green
Infrastructure (GI) measures show to be the most suitable focus to face the
challenges confronted by each city since it integrates a participatory approach
and environmentally sustainable solutions.
1. Nature
based Solutions (NbS) and Green Infrastructure (GI): conceptual background
Nature
based solutions (NbS) are inspired in the functioning of nature and its
processes; this approach pretends to solve problems (e.g. in the management of
water quality or the decrease of the impacts by water variability) that are
usually tackled by traditional methods or to improve the impacts of the ones
already used [4]. These solutions might be applied at micro or macro-scale and
must be proposed usually considering the local social and environmental
conditions of the place where they need to be applied. On the other hand, Green
Infrastructure (GI) is a network of natural and/or anthropogenic areas that are
connected to the urban or rural ecosystems and help the nature to better provide
ecosystem services and improve the human welfare by protecting the biodiversity
and regulating climate change [3, 13, 14]. GI includes “natural features, such
as parks, forest reserves, hedgerows, restored and intact wetlands and marine
areas, as well as man-made features, such as ecoducts and cycle paths” [12]
In
this respect, the GI operates based on NbS concepts, being the first somehow a
way to carry out the second. Due to the fact that the major element in the
sustainability of all the terrestrial and aquatic ecosystems is the water, the
NbS are mainly focused on the conservation of water quantity, improvement of
water quality and its role in natural risks such as droughts and floods.
2.
Focus of the GI measures for Darmstadt
and Leon cities
With
the aim of finding the most suitable solutions for the environmental, economic
and social concerns of the study area, it is necessary to gather information on
the characteristics of: historical weather records, distribution and influence
of natural hazards, water quality and quantity, distribution and relationship
with protected areas and national policies, etc. Taking all these factors into
account, a more appropriate approach can be performed.
In
consequence, the measures posed in this chapter follow the next principles:
- Alignment
with national and regional plans on restoration and expansion of
ecosystems, protected areas and increasing of ecological connectivity.
- Decentralization
of solutions with independent management.
- Articulation
of Society with the infrastructure through a participatory approach.
- Avoiding
at a minimum amount the “grey infrastructure” that behaves mechanically
fragile in high stress conditions such as seismic events.
- Assurance
of water supply in case of central supply system collapse or extreme natural
events (volcanic eruption, earthquakes, etc.), in this case only
considered for Leon city.
And
therefore, there are four cores for which the solutions here proposed are
intended to influence to:
·
NbS
for water management
·
NbS
for Climate regulation
·
NbS
for Ecological connectivity
·
NbS
for improving life quality (economic incomes, health and emotional balance)
3.
Case study: Rio Chiquito in Leon City
3.1.
Environmental background
The Nicaraguan Institute for Territorial
Studies [15] (INETER by its abbreviation in Spanish) has issued a series of
studies which describe detailly the climatic conditions of Nicaragua in order
to provide scientific data for decision takers. Despite of the regional
character of the studies and the wide scale, this information allows to make a
first approach to an environmental framework of the 100 Km² and its
relationship with other areas of the country as well as to interpolate data to
the 1 km² area of influence of Rio Chiquito.
According to INETER, the area of Leon is
defined according the Köppen Climatic Classification as hot and sub-humid with rainfall in summer and annual average temperature of 30°C. It typically presents a dry
season (November – April) with an average precipitation of 100 – 150 mm and a
rainy season (May – October) with an average precipitation of 1200 – 1600 mm.
The potential evapotranspiration
(PEVT) shows a value between 1800 and
2000 mm/y. Through the analysis of these first data, it is possible to
interpret that there is an unbalance in the hydric balance since there are (at
least theoretically) around 200 mm of precipitation less than PEVT. However,
this affirmation needs further analysis. Furthermore, the maximum absolute precipitation (MAP) recorded in Leon for a 24
hours period (between 1971 and 2000) has been recorded as 350 – 400 mm, which might be explained due to the geographic
position of the country, which leads it to be affected during the rainy season
by extraordinary extreme events such as: tropical depression, Tropical Storms
and hurricanes. One good example of this phenomena has been the Hurricane Mitch
in 1998 where precipitations of 825.5 mm in Malpaisillo, 15 km to the east of
Leon city [15]. At last, the data for relative
humidity indicates values between 70 – 80%.
Finally,
the climatic comfort index,
which describes the perception on several meteorological factors on the human well-being,
and that considers fundamentally: temperature, humidity, solar radiation and
wind is classified as: Very warm and oppressive.
It
is agreed by the international scientific community that due to Climate change
the extreme events will increase in magnitude, recurrence and intensity,
therefore this values are tend to increase.
3.2.
Natural
hazards background
The natural hazards level and distribution must be
considered when planning the development of green infrastructure and different
projects of incidence on the territories since these measures should involve conditions
for enduring after extreme events occurrence and permit the communities to
increase their resilience in front of adverse situations.
For the area of Leon city, there are two main kind
of natural hazards. In first place, the volcanic hazard accounts for a high
level of risk due to the proximity to a volcanic arc where most of the
volcanoes are active. The figure 1 shows the hazard zonation for a potential
eruption of one of the most active volcanoes in the mountain ridge [16]. In the
figure 2, Leon is placed in the level of seismic hazard as high [17].
Figure 1: Map of volcanic risk for Leon city in a probable eruption event of one
of the volcanoes in the volcanic arc. Source: PASCO. - INETER,
2006.
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Figure 2: Map of seismic risk of Nicaragua where Leon
places in the high level. Source: INETER, 2004.
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3.3.
Natural protected areas and regional
ecological connectivity
In
the surroundings of the Leon city there are several natural protected areas
categorized as National Parks [18],
five of them are placed in the mountain volcanic ridge and a sixth one is in
the pacific coastal area (Figure 3). Leon city, as the middle point among all
these important ecological and ecosystem services provider spots, plays an
important role since it might potentially connect the coast and the mountains
and improve the resilience of these ecosystems as well as provide a refuge for
biodiversity. In this regard, Rio Chiquito shows up as the corridor that could
through restoration and expansion programs improves the ecosystem services
provision for the region.
Figure 3: Map of areas of interests for conservation in
Nicaragua. Source: MARENA (2018).
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4.
Green Infrastructure and Nature based
Solutions for Rio Chiquito area
The
core of GI and NbS were devised to consider the specific natural and cultural
contexts of the region where to be applied and at the same time to integrate
the water management challenges with other community´s concerns. In that sense,
the formulation of the solutions shall involve a participatory and democratic
focus as well as understand the people´s perception of the problems to be
solved. However, due to the character of “first approximation” of this report,
some assumptions (of suitability and acceptance by the inhabitants of the
influence area) are made since there was not direct contact with local societal
groups or political and scientific authorities more than the comprehensive
review of secondary information.
The
urban and semiurban areas around the Rio Chiquito face nowadays several
conflicts that deteriorate its ecological status and in consequence the
provision of ecosystem services. Some of these are: bad social reputation of
the quarters, informal dumping sites along the river, insecurity around the
river, precarious living conditions of the communities adjacent to the river
and in the neighborhoods associated to the study area, few economic activities
and incomes generation, unorganized land planning, low social cohesion and community
organization, denudation- erosion processes that cause channel siltation,
deforestation of riparian corridors, uncontrolled urbanization, pollution of
water in the Rio Chiquito, land use conversion, burning practices and cattle
raising in river associated areas, pressure on river flow for irrigation
purposes and finally, dropping of water table and drying of artisan wells from
which some members of the community take water [19].
In
Table 1, are presented five different measures to carry out in the 1 km² area
surrounding Rio Chiquito with the aim to deal with the above-mentioned
conflicts and in turn the potential benefits of each of the measures are
presented.
Table
1: Green infrastructure and Nature based Solutions to face water conflicts in
the Rio Chiquito surrounding areas. In the first column, each color indicates a
different category of direct benefits, namely, green: ecological, blue: water
quality and quantity related problems, yellow: soil erosion and soil
protection, purple: integration and strengthening of society, and red: economic
incomes.
1.
Case study: Darmbach in Darmstadt City
1.1.
Environmental background
The
next environmental information of the Darmbach stream was taken from official
sources [20] and are not going to be specified extensively in this document. However,
it is important to remark that the average temperature in Darmstadt for winter is
2° C and for summer is 18° C, the precipitation for summer is around 200 – 225
mm, for winter 150 -175 mm, for autumn is 175-200 mm and for spring 175 mm. The
wind speed is 2,5 m/s at 10 m above the ground. Evapotranspiration value is
around 600 - 650 mm/a. The calculations for water balance show a surplus
between 0 – 100 mm. Finally, in accordance to the climate models for the next
decades, the precipitation is going to increase by 5-10% in average for winter and
between 15 - 25% for summer as well.
1.2.
Natural hazards background
There are not considerable natural hazards for the
Darmstadt region concerning to seismic, volcanic or flooding events. Nonetheless,
there are models that point out a change in temperature and precipitation for
the next decades [20], aspects which undoubtedly will influence the water cycle
and the stability of the ecosystems and their services if no adequate measures
to increase the resilience are taken. Therefore, it can be considered that the
most relevant natural hazard for this study area is climate change and
variability and one clear example is the summer 2018 when according to the
testimonies of inhabitants “the days with temperatures over 30 have been by far
many more than the last years”, fact that seems to be indicating the recurrence
in extreme hot days.
1.3.
Natural
protected areas and regional ecological connectivity
It
is relevant to highlight the relationship of the study areas (1 km² and 100 km²
area) compared to the protected areas for different purposes (flora and fauna
habitat, birds’ protection and water protection) (Figure 4). The water
protection areas (Figure 5) play an important role to tackle climate change and
variability and in consequence the GI measures must try to integrate them in
the functioning.
Figure 4: Distribution
of the protected areas around the 1 km² analysis area. In green color is
showed the Fauna and Flora habitat areas; in pink color is showed the bird
protection areas and in blue is showed another kind of nature protected area.
Source: http://atlas.umwelt.hessen.de/servlet/Frame/atlas/geologie/geo/erdbeben_txt.htm
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Figure 5: Distribution
of aquifer recharge protected zonation when land uses for I are the most
restrictive and IIIB the most permissive ones. the Source: http://atlas.umwelt.hessen.de/servlet/Frame/atlas/geologie/geo/erdbeben_txt.htm
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2.
Green Infrastructure and Nature based
Solutions for Darmbach area
The
case of the Darmbach stream is highly contrasting with the Rio Chiquito. While
the Darmbach does not present problems with dumping sites, negative social
perception of the communities living around the stream and land use conversion,
there are several other factors that are certainly affecting the ecological
status of the stream or elements that can be improved, namely: drastic decrease
of the stream flow in summer season, lack of area for riparian forest, lack of connectivity with other protected
areas, high amounts of phosphorous in solution, communities demanding
recreational spaces, need for revitalization of urban spaces, low sense of
belonging to the river and river bank erosion, etc. In the table 2, are
presented the GI and the NbS measures proposed to confront and solve with an
integral approach focus the challenges previously posed.
Table 2: Green infrastructure and Nature based Solutions to face water conflicts in
the Darmbach stream. In the first column, each color indicates a different
category of direct benefits, namely, green: ecological, blue: water quality and
quantity related problems, yellow: soil erosion and soil protection, purple:
integration and strengthening of society, and red: economic incomes.
References
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Millennium Ecosystem
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Vienna, Department of Political Science, Vienna, Austria.
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Beißler, M., (2018), Assessment of the
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11.
Darmstadtbach Project der Wissechaftsstadt Darmstadt - http://www.darmbach.de/abschnitte/tsg-bot/p_tsg-bot-garten.htm
12. European Comission, (2012), “Science for Environment Policy – The
multifunctionality of Green Infrastructure”.
13. Mazza L., Bennett G., De
Nocker L., Gantioler S., Losarcos L., Margerison C., Kaphengst T., McConville
A., Rayment M., ten Brink P., Tucker G., van Diggelen R. 2011. Green
Infrastructure Implementation and Efficiency. Final report for the European
Commission, DG Environment on Contract ENV.B.2/SER/2010/0059. Institute for
European Environmental Policy, Brussels and London. In this respect, the GI
operates based on NbS concepts, being the first somehow a way to carry out the
second. Due to the fact that the major element in the sustainability of all the
terrestrial and aquatic ecosystems is the water, the NbS are mainly focused on
the conservation of water quantity, improvement of water quality and its role
in natural risks such as droughts and floods.
14.
Comision Europea,
(2014), “Construir una infreaestructura verde para Europa”.
15.
Instituto Nicaragüense de Estudios Territoriales, (2005), “Caracterización climática de Nicaragua”, Managua. 7
16.
PASCO. - INETER., Asahina, T., Navarro
M. Mapas de Amenaza Volcánica de los volcanes Telica, El Hoyo Cerro Negro.,
2006
17.
INETER (2004), “Mapa de amenaza
sísmica de Nicaragua”.
18.
MARENA, (2018), “Mapas ambientales de
Nicaragua”
19.
CORRIOLS, M., (2010), “Estudios
geofísicos e hidrogeológicos para la caracterización del acuífero de León –
Chinandegua”, UNAN – Managua.
20.
http://atlas.umwelt.hessen.de/servlet/Frame/atlas/geologie/geo/erdbeben_txt.htm
. Consulted on 06 August, 2018.
Germany, August 2018
