WETLAND ASSESSMENT REPORT

WETLAND ASSESSMENT REPORT

SNNP IAIP AND RTC SITE

Report Produced by:

WSP in collaboration with Engineer Tequam Water Resources Development and

Environment Consultancy (ETWRDEC)

TABLE OF

CONTENTS

1

INTRODUCTION ... 5

2

KNOWLEDGE GAPS ... 5

3

AIMS AND OBJECTIVES ... 5

4

METHODOLOGY ... 5

Wetland Delineation ... 6

Wetland Classification ... 7

Present Ecological State ... 8

Functional Analysis ... 11

5

BASELINE ENVIRONMENT ... 12

Desktop Review ... 12

Results ... 13

6

SIGNIFICANT IMPACTS IDENTIFIED ... 18

Direct and Indirect ... 18

Cumulative ... 19

TABLES

TABLE 1: HYDROGEOMORPHIC CLASSES OF

SMITH ET AL. (1995) ... 7

TABLE 2: RAMSAR CONVENTION WETLAND

CLASSIFICATION ... 9

TABLE 3: ECOSYSTEM GOODS AND SERVICES

PROVIDED BY WETLAND HABITATS ... 11

TABLE 4: IDENTIFICATION OF WETLAND HABITAT

LOCATED WITHIN THE PROPOSED

DEVELOPMENT FOOTPRINT. ... 13

TABLE 5: IMPACT ASSESSMENT INCLUDING

PRE- AND POST-MITIGATION RATINGS ... 21

FIGURES

FIGURE 1: MAJOR WETLAND BIOMES IN ETHIOPIA

(BEZABIH AND MOSISSA 2017) ... 8 FIGURE 2: WETLAND UNITS WITHIN THE IAIP SITE ... 15

FIGURE 3: EXAMPLES OF THE WETLAND UNITS

1

INTRODUCTION

A wetland desktop screening and infield assessment, relating to the proposed SNNP IAIP development and the associated RTC site (‘the sites’) is required to satisfy the requirements of the ESIA.

The objective of the desktop screening assessment is to identify wetland habitats present on the site that require further assessment during the infield assessment. This is to determine whether the proposed sites may intrude into the delineated boundary of a wetland and therefore impacting on that system. The potential impacts of the proposed sites on any identified wetland will be assessed.

2

KNOWLEDGE GAPS

Key assumptions and limitations relevant to the assessment included:

— Wetlands identified for delineation were based on a desktop review of available information and a site inspection. This is reliant on various published data sources (e.g. aerial imagery and mapping).

— Whilst the desktop review and site investigation aimed to identify and assess all wetlands within the study area, wetlands not identified during this process did not form part of this study. Any additional systems identified during the construction phase must be afforded the same protection, mitigative measures and recommendations as outlined within this report.

— The wetland boundary comprises a gradually changing gradient of wetland indicators and varies both temporally and spatially; the wetland delineation thus occurs within a certain degree of tolerance.

— It should be recognised that there are several confounding effects on the interpretation of the historic and current extent and functioning of the respective systems such as the presence of infrastructure (roads, fencing, culverts etc.) and agricultural practices (e.g. vegetation removal, tilling, grazing, etc.).

— The wetland/riparian boundaries within the specific study area in relation to the proposed development and associated infrastructure were accurately delineated, based on the initial desktop review. The remaining watercourses were delineated at a desktop level and broadly verified in the field to obtain an extent of the wetland/riparian areas.

— This report has assessed the impact (on freshwater habitats) of the proposed IAIP and RTC sites only. — The findings, results, observations, conclusions and recommendations given in this report are based on

best scientific and professional knowledge as well as available information.

3

AIMS AND OBJECTIVES

The aim of the assessment is to determine the extent, health and functionality of freshwater habitats within proposed sites that have a potential risk of being impacted on by the proposed sites’ activities. The assessment was guided by the following objectives:

— Review of any existing literature on wetland systems within the study area or region; — Identification and delineation of wetland systems (desktop and infield);

— Description of the wetlands/wetland systems identified (if any);

— A description of the current state and functionality of the identified wetlands; and — Identification of current and potential impacts and any associated mitigation measures.

4

METHODOLOGY

— Desktop identification of watercourses within the boundary of the proposed sites; — Infield delineation and classification of watercourses within the proposed sites; — Functional assessments of the potentially impacted watercourses (i.e. PES, EIS). — Impact Assessment

The methods and tools utilised to conduct the freshwater habitat assessments within the study area were determined utilising desktop and infield assessments together with professional opinion. An in-depth description of each individual method is provided in the chapters that follow. Available datasets were utilised, to supplement the information gathered on site.

WETLAND DELINEATION

There are numerous definitions for wetlands, with no one definition being agreed upon on an international scale. This is attributed to different ideas on the boundary of between the aquatic system and the surround terrestrial environment and the natural variations in climatic conditions, hydrology, soils and vegetation communities. According to the Ethiopian Water Resources Management Policy the definition of a wetland is “areas of marsh, fen, peatland or water, whether natural or artificial, permanent or temporary, with water that is static or flowing, fresh, brackish or salt, including areas of marine water the depth of which at low tide does not exceed six meters”. This definition is also utilised within numerous papers published in internationally accepted Journals and papers within the International Union for Conservation of Nature and Natural Resources (IUCN) publication “Wetlands of Ethiopia. Proceedings of a seminar on the resources and status of Ethiopia's wetlands” (Abebe & Gehab, 2003).

Wetland delineation includes the confirmation of the occurrence of wetlands and a determination of the outermost edge of the wetland. Therefore the definition above was utilised to identify wetland areas within and around the SNNP IAIP and RTC sites. After these systems had been identified, the following wetland indicators were used to delineate the wetlands:

1 Terrain Unit Indicator

— Identify those parts of the landscape where wetlands are more likely to occur (potential position of a wetland in the landscape).

2 Soil Form and Wetness Indicator

— Identification of the morphological ‘signatures’ developed in the soil profile as a result of prolonged and frequent saturation (determined through soil sampling with a soil auger and examining the degree of soil mottling and gleying).

— Hydromorphic soil displays unique characteristics resulting from its prolonged and repeated saturation. Once a soil becomes saturated for an extended time, roots and microorganisms gradually consume the oxygen present in pore spaces in the soil. In an unsaturated soil, oxygen consumed in this way would be replenished by diffusion from the air at the soil surface.

— Once the oxygen in a saturated soil has been depleted, the soil effectively remains anaerobic. These anaerobic conditions make wetlands highly efficient in removing many pollutants from water, since the chemical mechanisms by which this is done need to take place in the absence of oxygen.

— Iron is one of the most abundant elements in soils, and is responsible for the red and brown colours of many soils. Once most of the iron has been dissolved out of a soil as a result of prolonged anaerobic conditions, the soil matrix is left a greyish, greenish or bluish colour, and is said to be gleyed.

— A fluctuating water table, common in wetlands that are seasonally or temporarily saturated, results in alternation between aerobic and anaerobic conditions in the soil. Lowering of the water table results in a switch from anaerobic to aerobic soil conditions, causing dissolved iron to return to an insoluble state and be deposited in the form of patches, or mottles, in the soil.

— Recurrence of this cycle of wetting and drying over many decades concentrates these bright, insoluble iron compounds. Thus, soil that is gleyed but has many mottles may be interpreted as indicating a zone

— The hydromorphic soils must display signs of wetness within 50cm of the soil surface. This depth has been chosen because experience internationally has shown that frequent saturation of the soil within 50cm of the surface is necessary to support hydrophytic vegetation.

3 Vegetation Indicator

— Identification of hydrophilic vegetation associated with frequently saturated soils (vegetation types present onsite)

— Plant communities undergo distinct changes in species composition as one moves along the wetness gradient from the centre of a wetland to its edge, and into adjacent terrestrial areas equipped to handle. Aquatic plants are not equipped to deal with the periodic drying that occurs in many wetlands, whereas terrestrial plants cannot handle long periods of flooding. Despite these constraints, certain plant species, known as hydrophytes, have developed mechanisms to deal with these stresses.

— Some species are only found in wetland environments, and are thus termed obligate hydrophytes, while others can occur in both wetland and non-wetland soils, and are known as facultative hydrophytes. In practice the soil wetness indicator tends to be the most important, with the other indicators playing a confirmatory role. The reason is that vegetation responds relatively quickly to changes in soil moisture regime or management and may be transformed; whereas the morphological indicators in the soil are far more permanent and will hold the signs of frequent saturation long after a wetland has been drained (perhaps for several centuries).

WETLAND CLASSIFICATION

In order to identify the wetland types, a characterisation of hydrogeomorphic (HGM) types was conducted. These have been defined based on the geomorphic setting of the wetland in the landscape (e.g. hillslope or valley bottom, whether drainage is open or closed), water source (surface water dominated or sub-surface water dominated), how water flows through the wetland (diffusely or channelled) and how water exits the wetland. Once these systems have been defined into individual HGM units they can be classified.

The HGM Approach considers structural components of the wetland and surrounding landscape such as plants, animals, hydrology, and soils; biological, chemical, and physical processes; and the interaction of these components and processes. Surrounding land use is addressed because it impacts structural components and processes in the wetland. Basic concepts of the HGM Approach were first published in Smith et al. (1995). The HGM Approach uses a hierarchical classification with seven current hydrogeomorphic classes (Table 1).

Table 1: Hydrogeomorphic classes of Smith et al. (1995)

Hydrogeomorphic Class (geomorphic setting) Water Source (dominant) Hydrodynamics (dominant)

Riverine Overbank flow from channel Unidirectional and horizontal

Depression Return flow from groundwater

and interflow

Vertical

Slope Return flow from groundwater Unidirectional, horizontal

Mineral soil flats Precipitation Vertical

Organic soil flats Precipitation Vertical

Estuarine fringe Overbank flow from estuary Bidirectional, horizontal

Lacustrine fringe Overbank flow from lake Bidirectional, horizontal

The Ramsar Convention classifies wetlands habitats into three main categories and these include: (1) marine/coastal wetlands; (2) inland wetlands; (3) man-made wetlands (Table 2). The marine and coastal wetlands include estuaries, inter-tidal marshes, brackish, saline and freshwater lagoons, mangrove swamps, as well as coral reefs and rocky marine shores such as sea cliffs. Inland wetlands refer to such areas as lakes, rivers, streams and creeks, waterfalls, marshes, peat lands and flooded meadows. Lastly, man-made wetlands include canals, aquaculture ponds, water storage areas and wastewater treatment areas (MEA, 2005). The codes are based upon the Ramsar Classification System for Wetland Type as approved by Recommendation

4.7 and amended by Resolutions VI.5 and VII.11 of the Conference of the Contracting Parties. The categories listed herein are intended to provide only a very broad framework to aid rapid identification of the main wetland habitats represented at each site.

Additionally, on a local scale wetlands are classified in Ethiopia based on ecological zones, hydrologic functions, geomorphologic formations and climatic conditions. These categories interlink to form four major biomes. These biomes are the afro-tropical highlands, the Somali-Musai, the Sudan- Guinea and the Sahelian zone groups (Tilahun et al., 1996) (Figure 1).

Figure 1: Major wetland biomes in Ethiopia (Bezabih and Mosissa 2017)

PRESENT ECOLOGICAL STATE

Wetland health or present state is defined as a measure of the deviation of wetland structure and function from the wetland’s natural reference condition (Butcher, 2003; Macfarlane et al. 2009). The hydrological, geomorphological and vegetation health components of the identified systems are described separately. Hydrology is defined in this context as the distribution and movement of water through a wetland and its soils. This module focuses on changes in water inputs as a result of changes in catchment activities and characteristics that affect water supply and its timing, as well as on modifications within the wetland that alter the water distribution and retention patterns within the wetland. Geomorphology is defined in this context as the distribution and retention patterns of sediment within the wetland. This module focuses on evaluating current geomorphic health through the presence of indicators of excessive sediment inputs and/or losses for clastic (minerogenic) and organic sediment (peat). Vegetation is defined in this context as the vegetation structural and compositional state. This module evaluates changes in vegetation composition and structure as a consequence of current and historic onsite transformation and/or disturbance.

Table 2: Ramsar Convention Wetland Classification

Marine/Coastal Wetlands Inland Wetlands Human-made wetlands

A Permanent shallow marine

waters

L Permanent inland deltas. 1 Aquaculture ponds

B Marine subtidal aquatic beds M Permanent rivers/streams/creeks 2 Ponds (generally below 8 ha).

C Coral reefs N Seasonal/intermittent/irregular

rivers/streams/creeks.

3 Irrigated land irrigation channels/ rice

fields.

D Rocky marine shores O Permanent freshwater lakes (over 8 ha) 4 Seasonally flooded agricultural land

E Sand, shingle or pebble

shores

P Seasonal/intermittent freshwater lakes (over 8

ha)

5 Salt exploitation sites

F Estuarine waters Q Permanent saline/brackish/alkaline lakes. 6 Water storage areas (generally over 8 ha).

G Intertidal mud, sand or salt

flats.

R Seasonal/intermittent saline/brackish/alkaline

lakes and flats.

7 Excavations gravel/brick/clay pits; borrow

pits, mining pools.

H Intertidal marshes Sp Permanent saline/brackish/alkaline

marshes/pools.

8 Wastewater treatment areas

I Intertidal forested wetlands Ss Seasonal/intermittent saline/brackish/alkaline

marshes/pools.

9 Canals and drainage channels, ditches.

J Coastal brackish/saline

lagoons

Tp Permanent freshwater marshes/pools (below 8

ha),

Zk(c) Karst and other subterranean hydrological systems human-made

K Coastal freshwater lagoons Ts Seasonal/intermittent freshwater marshes/pools

on inorganic soils Zk(a) Karst and other subterranean

hydrological systems

U Non-forested peatlands

Va Alpine wetlands

Vt Tundra wetlands

W Shrub-dominated wetlands

Marine/Coastal Wetlands Inland Wetlands Human-made wetlands

Xp Forested peatlands

Y Freshwater springs; oases.

Zg Geothermal wetlands

Zk(b) Karst and other subterranean hydrological systems, inland

Prior to assessment, the wetland is divided into hydrogeomorphic (HGM) units and their associated catchments. These are analysed separately for hydrological, geomorphological and vegetation health based on infield investigations using both an impact-based and indicator-based approach:

— An impact-based approach to those activities do not produce clearly visible responses in wetland structure and function. The impact of irrigation or afforestation in the catchment, for example, produces invisible impacts on water inputs. This is the main approach used in the hydrological analysis.

— An indicator-based approach for activities that produce clearly visible responses in wetland structure and function such as the presence of erosion gullies or alien plant species. This approach is mainly used in the analysis of geomorphological and vegetation health.

FUNCTIONAL ANALYSIS

Wetlands perform a wide variety of ecological functions including provisioning of habitat for wildlife, purification of catchment surface water, floodwater attenuation, groundwater recharge, climate regulation and erosion control (Hey and Philippi, 1995; Costanza et al., 1997; Bunn et al., 1999; Mitsch and Gosselink, 2000; Adhikari and Bajracharaya, 2009; Jacobs et al., 2009). Furthermore, wetlands play a vital role in providing a wide range of ecosystem services for millions of people mainly living in developing countries (Shewaye, 2008; Teferi et al., 2010).

Functional assessments were developed principally for evaluating the potential impacts of developments which threaten wetland ecosystems, and are used to assess the success of wetland rehabilitation projects, by evaluating the change in wetland functioning over time (US EPA 1998f). These protocols are usually designed to estimate the change in functioning resulting from the alteration of a wetland (either positive or negative), utilising minimally-impacted wetlands (within each wetland class) as a reference or benchmark. Each function is scored relative to that of a reference wetlands in the same locality and class/type and subclass/subtype. The index value of each variable is accompanied by descriptions of estimates and measurements.

Eco-services refer to the benefits obtained from ecosystems. These benefits may be derived from outputs that can be consumed directly; indirectly (which arise from functions or attributes occurring within the ecosystem), or possible future direct or indirect uses (Howe et al., 1991) (Table 3). The values (goods) and services that wetlands provide can be broadly categorised as:

— Functions: flood alleviation, erosion control, stream flow regulation, water storage, ground water recharge, retention of pollutants, water purification, nutrient cycling, exchange of water between the surface and the groundwater and the surface and the atmosphere.

— Products: fish, fuel wood, timber, fodder for domestic animals, habitat for wetland-dependant species, rich sediments used for agriculture in the floodplains, fibre for thatching roofs and handicrafts.

— Attributes: diversity of species, aesthetic beauty, cultural heritage, tourist attractions, and recreation such as bird watching, sailing, education and archaeology.

Table 3: Ecosystem Goods and Services provided by wetland habitats

Direct Benefits Indirect Benefits

Cultural benefits — Cultural heritage — Tourism and recreation — Education and research

Regulating and supporting benefits — Flood attenuation

— Streamflow regulation — Carbon storage Provisioning benefits

— Provision of cultivated foods — Provision of harvestable resources — Provision of water for human use

— Biodiversity maintenance (red data, unique and/or migratory species; breeding/feeding site; diversity of habitats; size and rarity of the wetland type

Water quality enhancement benefits — Sediment trapping

— Phosphate assimilation — Nitrate assimilation — Toxicant assimilation — Erosion control

5

BASELINE ENVIRONMENT

DESKTOP REVIEW

Wetlands are estimated to cover about 6% of the earth’s surface, approximately 5.7 million km2 _{(WCMC, 1992).} Africa has 345,000 km2 _{of wetlands, equating to 1% of its surface area (Finlayson and Moser, 1991). Ethiopia} has more than 58 different types of wetlands which provide significant socio-economic and environmental values. Despite their small area coverage, wetlands in Ethiopia are among the most productive ecosystems, and have significant economic, social, and environmental benefits. The importance of Ethiopian wetlands goes beyond their status as habitat of many endangered flora and fauna species but they are a vital element of national and global ecosystems and economies (Mengesha 2017). Despite all this and other indispensable values, these wetlands are under severe pressure and degradation (Seid, 2017).

Globally, wetlands are under significant pressure through loss and degradation despite their critical role in providing socio-economic and ecological benefits within the larger landscape (Dahl, 1990; Dugan, 1990; Wolfson et al., 2002; Abebe & Gehab, 2003; Finlayson and D’Cruz, 2005; Mereta 2013; Bezabih & Mosissa 2017; Gebresllassie 2017; Mengesha 2017; Seid 2017). According to the Millennium Ecosystem Assessment (MEA, 2015) and McCartney et al. (2010) the loss and degradation of wetlands, globally, has been driven by expansion of human settlement, irrigation agriculture, water withdrawal, industrial pollution, overexploitation and introduction of invasive alien species.

The most common threats to wetlands are the result of a combination of social, economic and climatic factors, which have increased pressure on the natural resources in Ethiopian wetlands. Wetlands in Ethiopia are being transformed and altered at a significant rate into what many people consider better alternative uses.

The main activities resulting in the transformation of wetland habitat in Ethiopia include the unregulated conversion for agricultural production (including draining and diversion of water), overgrazing, clearance and overharvesting of vegetation and appearance of alien invasive plant species (Desta and Mengistou, 2009; Kassa and Teshome, 2015; Mengesha, 2017; Seid, 2017). Another constraint to the sustainable use of African wetlands is lack of knowledge by planners and natural resource managers of the benefits that specific wetland habitats provide and techniques by which these habitats be utilised in a sustainable manner (Mengesha, 2017). As population pressure increases, there is further limited access to farmland. These farmers therefore encroach into wetlands and forest areas for conversion into agricultural land. Moreover, poor households sell firewood and charcoal (sourced from wetland areas) to cope with food insecurity (Mengesha, 2017).

The impacted wetlands provide various socioeconomic and ecological benefits to society, which are or have the ability to significantly improve the livelihood of the communities surrounding the wetland systems. As the level of wetland degradation increases their benefit is also reduced (Kassa and Teshome, 2015).

Ethiopia has not yet ratified the Ramsar Convention on wetlands and, therefore, none of the identified 25 potential Ramsar wetlands in the country is designated in the list of wetlands of international importance (Mereta, 2013; Harper et al., 2016). Regardless of their vital role in food security and rural livelihood, the extent, diversity, distribution and conservation status of wetlands in Ethiopia is not well documented. Furthermore, there are no clear policies and strategies that protect wetlands in the country. Although wetland related issues are included in Ethiopian water resources, agricultural and environmental policies, the implementation of wetland management and conservation in the context of the above policies is compounded by a ‘more pressing wetland task force, extension package and food security policies that may seek to convert wetlands for agricultural purposes’ (Mereta 2013).

In Ethiopia, there is a lack of efficient and sufficient coordination and policy support, relating to wetland management. Due to the absence of workable institutional arrangement and wetland management policy,

Even though wetlands produce an ecological equilibrium in the environment, maintaining the integrity of life support systems for sustainable socio-economic development; many wetland ecosystems are regarded as wastelands and continue to be depleted at an alarming rate throughout Ethiopia (Abebe & Gehab 2003).

RESULTS

5.2.1 WETLAND DELINEATION

An in-depth desktop assessment, utilising aerial imagery (2012 - 2016) and available datasets, was conducted to determine potential freshwater habitats. This desktop analysis was vital due to the extent of the area under assessment. An infield assessment was conducted during August 2017 and the confirmed systems were delineated and assessed, along with additional systems identified during the infield assessment. A total of seven (7) wetland habitats were identified on the IAIP site, which comprise of artificial and natural depressions. The only river /stream system on the IAIP site is an ephemeral channel location along the north-eastern boundary of the site. The major watercourse in the region is the Gidabo River which runs along the western boundary of the site in a south-westerly direction (Figure 2). The RTC site did not contain any wetland habitat within its boundary.

5.2.2 WETLAND CLASSIFICATION

The identified systems were classified into respective HGM units, with some units being grouped into complexes (Figure 2, Figure 3 and Table 4).

Table 4: Identification of wetland habitat located within the proposed development footprint.

Project Code Ramsar Classification HGM Unit (Smith et al 1995) Ethiopian

Biome Nature Co-ordinates

W1 Seasonal/intermittent freshwater marshes/pools on inorganic soils (Ts) Depression Somali - Masai Natural 427806.02 m E 743527.15 m N W2 Depression Natural 427837.00 m E 743744.00 m N W3 Depression Natural 428449.00 m E 743377.00 m N W4 Depression Natural 428564.00 m E 745504.00 m N W5 Depression Natural 428761.00 m E 744100.00 m N

W6 Pond (2) Depression Artificial 428734.00 m

E

744318.00 m N

W7 Pond (2) Depression Artificial 427657.20 m

E 744506.04 m N R1 Seasonal/intermittent/ irregular rivers/ streams/ creeks (N) Riverine Natural 428798.61 m E 744963.32 m N The riverine system (R1) is a minor ephemeral channel, located within a valley floor that carries intermittent unidirectional longitudinal flows. The water inputs are mainly from channel entering the system and also from overland flow from adjacent valley-side slopes. There was no flowing water during the site visit which was conducted during the rainy season. The system and its micro-catchment are denuded of vegetation and significantly eroded downstream, outside of the site boundary. Water is usually lost from the system via diffuse surface flow and interflow into adjacent

The depression wetland units (W1-W7) identified onsite are characterised by their endorheic character and are circular to oval shape. They occur in relatively small enclosed basins and are typically ephemeral in nature, typically being filled with shallow water levels during the rainy season. There are also systems that appear to be perennial in nature however this is only due to anthropogenic excavations to create yearlong water sources. The dominant water inputs and outputs are dictated primarily by the outflow and inflow drainage characteristics. The hydrodynamics of these depressions are, however, typically dominated by vertical water level fluctuations. The depressions do not have any outward (downstream) drainage or any inflow channels and therefore are not connected to a river network and are considered ‘isolated depressions’.

5.2.3 PRESENT ECOLOGICAL STATE

The W1 - 5 depression wetlands are considered to be natural in origin with the units ranging from minimal to serious modifications having occurred. W2 and W4 are in a near-natural state with W1 and W5 having experienced significant excavations. These systems are still however functioning and providing goods and services within the natural environment. W6-7 are artificial systems created by excavating to below the water table creating a ‘pond’ system.

All the depressions besides W2 is devoid of vegetation with wetland obligate species being present only around the fringes of the system, attributed to the anthropogenic excavations creating permanent waterbodies. The various micro-catchments have been transformed from natural vegetation to agricultural land for crop production and grazing, dominated by the graminoid species Cynodon dactylon.

The catchment impacts include landscape transformation from the natural state due to informal housing, unpaved road infrastructure, livestock/human tracks, grazing and subsistence farming practices. These impacts have resulted in modified surface runoff regimes as there is a reduction in surface roughness and modified soil permeability. Alien invasive plant species such as Eucalyptus grandis are also present within the catchment in disturbed areas. Soil erosion is largely restricted to outside the site boundary however active gully formation has resulted in instability of the soil profile along the western boundary of the site.

The ephemeral channel (R1) is exposed to significant erosive forces from concentrated flow of stormwater. The catchment along the middle and lower reaches of the system is devoid of vegetation and eroded down to bedrock in many places. Additionally erosion (incision of the bed of the channel) and sedimentation has occurred within the R1 system itself.

A major indirect factor resulting in the degradation of the wetlands’ current state is poverty. The wetland resources are utilised in an attempt to make a livelihood, however as these are limited resources they have been over exploited (Dabassa 2010). The vegetation resources have been denuded and the majority of the bird and other wild fauna species have left these wetlands (and the surround catchments) due to loss or transformation of their natural habitats, i.e. trees have been removed and grasses been overgrazed (EPA 2004). Grazing is a direct threat to these wetlands in addition to the above factors. Due to historic grazing followed by cultivation; wetlands and their catchments easily became degraded, and lost their natural characteristics (consequently their resources as well) as with the IAIP site. The livestock lead to soil compaction and vegetation loss as they trample the soil and compact it, resulting in the transformation of the natural vegetation (Coates et

al. 2010). They have eroded drainage channels leading to gullies and increase water outflow. These effects

have resulted in the degradation of the wetlands and their catchments by reducing the water table and by changing the original vegetation (Mengesha 2017).

5.2.4 FUNCTIONAL ASSESSMENT

The typical functionality of depression wetlands tends to contribute less towards flood attenuation, but would supply this benefit to a certain extent and would be limited by the position of the system in the landscape. They naturally capture runoff, during stormflow conditions, due to the inward draining characteristic, and therefore to some extent aid in reducing the volume of surface water that would otherwise enter the natural systems in the area unattenuated. However this inward draining also means these systems don’t typically supply a streamflow regulation function. The potential for removal of nutrients and toxicants would generally be expected to some degree.

Nitrogen cycling is likely to be important with some losses due to de-nitrification, and volatilization in the case of high pHs. Water quality in pans is influenced by the pedology, geology, and local climate. These factors, in turn, also influence the response of these systems to nutrient inputs. In pans that dry out completely at some stage or another (non-perennial pans), some of the accumulated salts and nutrients (such as organic nitrogen, and various phosphate and sulphate salts) can be transported out of the system by wind and be deposited on the surrounding slopes. Those remaining may dissolve again when waters enter the system again as the pan fills after rainfall events (Kotze et al. 2009).

Wetlands are important in biogeochemical cycling, involves the biological, physical, and chemical transformations of various nutrients within the biota, soils, water, and air (Yang et al., 2008). Wetlands are very important in this regard, particularly relating to nitrogen, phosphorous and carbon. Nitrogen transformations in

wetlands are complex due to the multiple oxidation states of nitrogen molecule (Davidsson and Mattias, 2000; Bohlen and Gathumbi, 2007; Vymazal, 2007). The major transformations include mineralization of organic nitrogen, ammonia volatilization, nitrification, nitrogen fixation, plant uptake, denitrification, anaerobic ammonia oxidation, fragmentation, sorption, desorption, burial and leaching (Davidsson and Mattias, 2000; Vymazal, 2007). Mineralization of organic nitrogen in sediments provides the major source of nitrogen to wetland plants and is responsible for the high rates of productivity of many wetlands ecosystems (Bohlen and Gathumbi, 2007). Phosphorous has no significant atmospheric flux and has a much longer temporal biogeochemical cycle than nitrogen (White et al., 2000). Slow water flow through a wetland is essential for settling of particulate phosphorous (Van der Valk et al., 1978). Wetlands are one of the most effective ecosystems for storing soil carbon (Schlensinger, 1997) (Mereta 2013)

The depression wetlands do not provide streamflow regulation, erosion control, sediment trapping or phosphate removal to any significant extent. There is a slight flood attenuation benefit due to their storage ability however this is limited (only really effective early in the wet season) due the systems being at capacity fairly early on the wet season. There is also minor nitrates and toxicant removal attributed to the systems.

There is no to minimal provision in terms of cultivated foods, tourism/recreation, education/research and/or socio-cultural aspects derived directly from these systems. This is mostly due to the lack of vegetation cover, lack of endangered species and available harvestable resources. Due to the low organic content and subsequent lack of peat all the systems are not significant in terms of carbon storage. The provision of water for human use is the only benefit that is considered a significant service provided by wetland W1,W3 & W5. However wetland size plays a major role in the contributing to the provision of particular benefits. The size of wetland in relation to benefits such as flood attenuation, sediment trapping and phosphate assimilation is always very important; with nitrate and toxicant removal, erosion control, cultivated foods and carbon storage usually being determined by wetland size. The ability for the systems to provide goods and services such as water supply, streamflow regulation and biodiversity maintenance is less dependent on the size of the systems. Therefore as the systems are small in extent and isolated, the ability to provide the abovementioned goods and services is further hindered.

6

SIGNIFICANT IMPACTS IDENTIFIED

DIRECT AND INDIRECT

The Integrated Water Resource Management (IWRM) is an internationally-accepted approach to sustainable Water Resource Management. It recognises the inter-relatedness and relationship between watercourse level processes and components (resource quality characteristics). An activity associated with the existing development can impact any of the resource ecosystem drivers (flow regime, water quality, geomorphological) or responses (habitat, biota) and this will have a knock-on effect on potentially all the other drivers and or responses.Therefore, when assessing an activity, the impact that specific activity may have on all the resource quality characteristics is assessed. The majority of activities will not only affect one characteristic due to their complex interrelatedness.

The potential direct and indirect impacts of the proposed development on the identified wetland habitats are discussed below.

The proposed development may potentially impact the depression systems, however the area where the proposed activities are proposed to occur has already been significantly modified by the current and past land and water use activities. The majority of the potential impacts will occur during the construction phase. The long-term impacts that are likely to occur relate to the onsite stormwater management during the operational phase of the proposed development.

will direct water away from subsurface pathways to overland flow into the stormwater drainage system. The difference in permeable area between the undeveloped site and that of the proposed development may result in: the increase in flood frequency and intensity, decrease infiltration, alter flow patterns, increase concentrated runoff, potential erosion (i.e. increase in flow velocity, especially considering the high erodibility of the soils) and widening of river’s banks and channel in the surrounding areas. It is recognised that some level of permeability has been designed for within the drain structures. Effective stormwater management would allow for the release of the surface water runoff in a controlled manner, with minimal impact on the surrounding environment. The quality of the surface water runoff from the proposed development may result in the degradation of water quality downstream of the site. Again an effective stormwater management plan for the proposed development, including structures such as grease traps, would mitigate against this impact.

The quality of the surface water runoff from the proposed development may result in the degradation of water quality downstream of the site. Again an effective stormwater management plan for the proposed development, including structures such as grease traps, would mitigate against this impact.

Mitigation requires proactive planning that is enabled through a mitigation hierarchy. This is in line with relevant requirements in the African Development Bank’s operational safeguards (ADB 2015). Its application, is intended to strive to first avoid disturbance of ecosystems and loss of biodiversity, and where this cannot be avoided altogether, to minimise, rehabilitate, and then, as a last resort, compensate for and offset any remaining significant residual negative impacts on biodiversity.

The implementation of this mitigation hierarchy is required to be shown as the complete removal of the identified systems and compensation/offset (final step in hierarchy) of removed systems can only occur once the avoid, minimise and rehabilitate steps have been considered and proved to be not possible. Ideally 100% of the wetland systems would be maintained and incorporated into the detailed designs of the IAIP (‘avoid’ in the mitigation hierarchy), however it is noted that this may not be feasible due to social and economic factors and project viability criteria. It is also noted that the systems proposed to be removed are small isolated systems low in provision of goods and services, therefore considered low in conservation value. Therefore the loss of wetland habitat, which is the most significant impact, can be mitigated against to result in ‘no net loss of biodiversity’ as a result of the proposed development through the implementation of protection strategies (Table 5).

The specific impacts outlined in Table 5, are overarching general impact categories that may result as a consequence of the proposed development on the wetland systems. These are broad categories that encapsulate the impacts that could potentially affect the functioning of a wetland system. Mitigation measures are also included to minimise the identified impacts. The decommissioning impacts and mitigation measures have also been included.

CUMULATIVE

According to Dixon and Wood (2003) wetlands in Ethiopia are often perceived as impediments to development and progress or as productive lands suitable for agriculture. The Ethiopian government encouraged farmers to cultivate wetlands to compensate for more drought-induced food shortages. The Rural Agricultural Development Department also developed its own programmes for draining some larger wetlands for agriculture (Wood, 2000). In southwest Ethiopia, for example, the area of wetlands converted to agricultural land increased from 28% in 2003 to 66% in 2006 (Legesse, 2007). Similarly, a number of microfinance initiative groups were established in several towns to cultivate peri-urban wetlands and produce bricks from wetland material. Consequently, several wetlands in Ethiopia, either disappeared or are on the verge of drying out (Shewaye, 2008), while others rapidly decline in water quality (Mereta et al., 2012).

In addition, the wetlands have been considered as wastelands and seen as nuisance to human development (Dixon and Wood 2003; Bezabih and Mosissa 2017). This view has led to considerable conversion of wetlands, which has usually been seen as a progressive public-spirited endeavor believed to enhance the health and welfare of society, alleviate flooding, improve sanitation and land reclamation. Moreover, the underlying causes of wetland loss are that they are assumed to be less important than other priorities or tend to be regarded as free goods (Bezabih and Mosissa 2017).

This continued conversion or degradation of individual wetland systems has resulted in a cumulative loss of wetland habitat at the landscape level within Ethiopia. The majority of the cumulative hydrological impacts manifest downstream due to altered stream flow processes, e.g. the loss of a wetland upstream which provided a function of streamflow regulation will result in water input into a downstream system containing higher volumes

and velocity and therefore a higher erosive force. This will result in the erosion and potential loss of the downstream wetland, which then potentially will result in the wetland system further downstream being impacted and so forth (Johnston, 1994).

As the systems identified within the IAIP site are small isolated systems which have already been significantly impacted, are minimal in size and currently provide minimal goods and services; the cumulative impacts are deemed to be minimal relating to this development, especially considering that artificial systems are proposed within the proposed layout. These artificial systems may be managed to ensure the ecological state of the systems are maintained as near-natural as possible, resulting in improved goods and services. The cumulative impacts have been assessed for the IAIP site (Table 5).

Table 5: Impact Assessment including pre- and post-mitigation ratings

CONSTRUCTION Impact

number

Recept

or Description Stage Character

Ease of Mitigation

Pre-Mitigation Mitigation Measure Post-Mitigation

Probability Severity Significance Rating Description Probabilit

y Severit y Significan ce Ratin g Impact 1: W1-7; R1

Direct loss/ degradation of natural wetland habitat & biota

Constructio

n Negative Nil 4 4 16 N4

— No mitigation possible as the wetland

habitats are completely removed. 4 4 16 N4

Significance N4 - Major N4 - Major

Impact 2: W1-7; R1 Hydrological functioning/regime modifications Constructio n Negative Low 4 2 8 N3

— No mitigation possible as the wetland

habitats are completely removed. 4 2 8 N3

significance N3 - Moderate N3 - Moderate

Impact 3: W3; R1 Erosion and Sedimentation Constructio

n Negative Moderate 4 3 12 N4

— These systems are located on the boundary and continue outside the boundary of the IAIP. No contaminated runoff must be allowed to enter these systems during construction. A construction stormwater management plan must be compiled and approved by the relevant authority to ensure all surface onsite during construction is managed in the most environmentally friendly manner.

— The use of energy dissipaters at all stormwater discharge points needs to be implemented during both construction and operational phases. All stormwater outlet structures must be located outside of the identified systems with some allowance for outlet protection e.g. reno-mattresses or rock packs).

— Ideally construction should occur during the dry season.

2 2 4 N2

Significance N4 - Major N2 - Minor

Impact 4: W3; R1 Water Quality Constructio

n Negative High 3 2 6 N3

— These systems are located on the boundary and continue outside the boundary of the IAIP. No contaminated runoff must be allowed to enter these systems.

No dumping of construction waste must occur within these systems.

2 2 4 N2

OPERATIONAL Impact

number Receptor Description Stage Character

Ease of Mitigation Pre-Mitigation Mitigation Measure Post-Mitigation

Probability Severity Significance Rating Description Probability Severity Significance Rating

Impact 1: Artificial

systems

Direct loss/ degradation of natural wetland habitat & biota (Offsetting wetland loss through the creation and management of artificial wetland habitats)

Operational Positive High 1 1 1 P1

— Creation of waterbodies within the site to offset the loss of the isolated depressions.

— These would be artificial isolated systems providing islands of aquatic habitat. There are provisions made for open waterbodies within the landscape plan, which would be able to provide similar services as the current waterbodies are providing. This is under the assumption that the waterbodies in the plan will be designed as far as possible to represent ‘natural’ systems. It is important that the correct species be utilised when constructing these waterbodies and that an operational maintenance plan is developed to ensure these waterbodies are maintained in a state that will continue to provide isolated habitat for aquatic-dependent species. The plan must include the control and maintenance of sediment and nutrient input into these systems to prevent sedimentation and potential eutrophication.

— The through-flow or circulation of water is also important to ensure water doesn’t stagnate. The use of certain species such as Typha and Cyperus species must be managed to ensure they do not form dense communities throughout the

waterbody resulting in a homogenous community (low biodiversity) and limited to no open water areas (decreasing habitat diversity). The maintenance of these systems will result in micro-hotspots of

biodiversity that has the potential of supporting a variety of floral and faunal species.

OPERATIONAL Impact

number Receptor Description Stage Character

Ease of Mitigation Pre-Mitigation Mitigation Measure Post-Mitigation

Probability Severity Significance Rating Description Probability Severity Significance Rating

with sensitive areas sucha as the newly created artificial systems.

Significance P1 - Negligible P4 - Major

Impact 2: Artificial systems; W3; R1 Hydrological functioning/regime modifications

Operational Negative High 4 2 8 N3

— The operational stormwater management system for the proposed development must be designed to ensure that runoff regimes post-construction activities matches that regimes

pre-construction (i.e. without resulting in increased peak discharge to water resources, soil saturation in non-wetland areas and erosion/ sedimentation). All outlets must be designed to dissipate the energy of outgoing flows to levels that present a low erosion risk.

— The through-flow or circulation of water is also important to ensure water doesn’t stagnate.

2 1 2 N2

OPERATIONAL Impact

number Receptor Description Stage Character

Ease of Mitigation Pre-Mitigation Mitigation Measure Post-Mitigation

Probability Severity Significance Rating Description Probability Severity Significance Rating

Impact 3:

Artificial systems; W3; R1

Erosion and Sedimentation Operational Negative Moderate 4 4 16 N4

— The stormwater management system for the proposed development must be designed to ensure that runoff regimes post-construction activities matches that regimes

pre-construction (i.e. without resulting in increased peak discharge to water resources, soil saturation in non-wetland areas and erosion/ sedimentation).

— All outlets must be designed to dissipate the energy of outgoing flows to levels that present a low erosion risk.

The use of sediment curtains is encouraged especially within downstream reaches of the R1 system.

2 2 4 N2

Significance N4 - Major N2 - Minor

Impact 4: W3; R1 Water Quality Operational Negative Moderate 3 2 6 N3

— No contaminated runoff from the site must be allowed to enter these systems. Any stormwater directed into these systems must not result in erosion and subsequent

sedimentation of the water profile (sediment load).

— The quality of water exiting the site should be monitored in accordance with an approved monitoring

programme to ensure the water from the site is not having a long-term adverse effect on the systems surrounding the site.

2 1 2 N2

DECOMISSIONING Impact

number Receptor Description Stage Character

Ease of Mitigatio n Pre-Mitigation Mitigation Measure Post-Mitigation

(M+ E+ S Rating Description (M+ E+ S Rating

Impact 1: Artificial systems; W3; R1 Direct loss/ degradation of natural and artificial wetland habitat & biota

Decommissioning Negative High 4 4 16 N4

— The established artificial wetlands must be provided a No-go buffer before decommissioning occurs. These systems and the associated buffer must not be impacted upon during decommissioning.

1 1 1 N1

Significance N4 - Major N1 - Negligible

Impact 2: Artificial

systems

Hydrological functioning/regime modifications

Decommissioning Negative Low 3 3 9 N3

— As there will no longer be active management of these systems the hydrological regime will be impacted upon. This cannot be mitigated against.

3 3 9 N3

Significance N3 - Moderate N3 - Moderate

Impact 3: Artificial systems; W3; R1 Erosion, Sedimentation and Water Quality

Decommissioning Negative Moderate 4 4 16 N4

— The footprint of the decommissioned site must be rehabilitated to a near-natural state utilising appropriate indigenous species. This will prevent the formation of erosional features and subsequent sedimentation of the systems

2 2 4 N2

Significance N4 - Major N2 - Minor

CUMULATIVE Impact

number Receptor Description Stage Character

Ease of Mitigation

Pre-Mitigation Mitigation Measure Post-Mitigation

(M+ E+ S Rating Description (M+ E+ S Rating

Impact 1: Wetlands within greater landscape Decrease in average area of individual wetlands

Cumulative Negative High 3 3 9 N3

— Creation of waterbodies within the site to offset the loss of the isolated depressions.

— These would be artificial isolated systems providing islands of aquatic habitat. There are provisions made for open waterbodies within the landscape plan, which would be able to provide similar services as the current waterbodies are providing.

— This is under the assumption that the waterbodies in the plan will be designed as far as possible to represent ‘natural’ systems. It is important that the correct species be utilised when constructing these waterbodies and that an

operational maintenance plan is developed to ensure these waterbodies are maintained in a state that will continue to provide isolated habitat for aquatic-dependent species. The plan must include the control and maintenance of sediment and nutrient input into these systems to prevent sedimentation and potential eutrophication.

— The through-flow or circulation of water is also important to ensure water doesn’t stagnate. The use of certain species such as Typha and Cyperus species must be managed to ensure they do not form dense communities

1 1 1 N1

Significance N3 - Moderate N1 - Negligible

Impact 2: Wetlands within greater landscape Change in proportion of wetland types

Cumulative Negative High 3 3 9 N3 1 1 1 N1

Significance N3 - Moderate N1 - Negligible

Impact 3: Wetlands within greater landscape Shift in spatial configuration of wetlands

Cumulative Negative Moderate 3 3 9 N3 1 2 2 N2

Significance N3 - Moderate N2 - Minor

Impact 4: Wetlands within greater landscape Change in cumulative wetland function

throughout the waterbody resulting in a homogenous community (low

biodiversity) and limited to no open water areas (decreasing habitat diversity). The maintenance of these systems will result in micro-hotspots of biodiversity that has the potential of supporting a variety of floral and faunal species.

7

REFERENCES

— Abebe Y, Gheb K (eds). 2003. Wetlands of Ethiopia. Proceedings of a seminar on the resources and status

of Ethiopian's wetlands: vi+116pp. IUCN- Eastern Africa Regional office, Narobi, Kenya.

— Abunje, l. 2003. The distribution and status of Ethiopian wetlands: an overview. In proceedings of a conference on Wetlands of Ethiopia. pp.12-18

— African Development Bank Group (ADB). 2015. Safeguards and sustainability series. Vol. 2(1). Volume 3: Sectors Keysheets.

— Barbier EB, Acreman MC, Knowler D. 1996. Economic Valuation of Wetlands: A guide for Policy-makers

and Planners. Ramsar Convention Bureau. Gland Switzerland.

— Bezabih, B. and Mosissa, T. 2017. Review on distribution, importance, threats and consequences of wetland

degradation in Ethiopia. International Journal of Water Resources and Environmental Engineering. 9(3):

64-71

— Birhan, M., Sahlu, S., & Getiye, Z. (2015). Assessment of Challenges and Opportunities of Bee Keeping in and around Gondar, 8(3), 127–131.

— Coates F., Tolsma A., Cutler S., Fletcher M. 2010. The floristic values of wetlands in the Highlands and Strathbogie Ranges School of Resource Management and Geography. The University of Melbourne. Parkville

— Dahl, T.E., 1990. Wetland Losses in the United States 1780s to 1980s. US Department of the Interior, Fish and Wildlife Service, Washington, DC.

— Dixon, A.B., Wood, A. 2003. Local Institutions for Wetland Management in Ethiopia: Sustainability and State Intervention. pp130-146 in Community-based water law and water resource management in developing countries. Van Koppen, B., M. Giordano, and J. Butterworth (eds.). Biddles Ltd, King’s Lynn UK.

— Dugan, P. J. (ed.). 1990. Wetland Conservation: A Review of Current Issues and Required Action. IUCN, Gland, Switzerland.

— Desta H, Mengistou, S. 2009. Water quality parameters and macro invertebrates index of biotic integrity of

the Jimma wetlands, southwestern Ethiopia. J Wetlands Ecology. 3: 77-93.

— Erwin J, 2003. WWF: Rapid Assessment and Prioritization of Protected Area Management (RAPPAM)

Methodology. World Wide Fund for Nature, Gland, Switzerland.

— EPA - Ethiopian Environmental Authority (2004) Proceedings of the “National consultative Workshop on the Ramsar convention and Ethiopia”, March 18-19, Addis Ababa, Ethiopia.

— Finlayson, C.M. and R. D’Cruz, 2005. Inland Water Systems in Millennium Ecosystem Assessment,

Conditions and Trends. Washington, D.C., USA: Island Press

— Gemechu Bekele Dabassa (2010) The Challenges and Opportunities of Wetlands Management in Ethiopia: The Case of Abijiata Lake Wetlands. MSc Thesis in Addis Ababa University

— Harper, D. M., Tebbs, E., Bell, O. and Robinson, V. J. Conservation and Management of East Africa’s Soda

Lakes, pg. 345-365. In: Schagerl, M. (ed). 2016. Soda Lakes of East Africa. Springer International,

Switzerland.

— Johnston, C.A. 1994. Cumulative impacts to wetlands. Wetlands 14(1): 49-55

— Legesse, T., 2007. The dynamics of wetland ecosystems: A case study on hydrologic dynamics of the wetlands of Ilu Abba Bora Highlands, South-West Ethiopia. Master Thesis, Human Ecology, Brussels. — MEA, 2005. Ecosystem and human well-being: Wetland and water synthesis. World Water Resources

Institute, Washington, DC

— McCartney, M., Rebelo, L-M., Sellamuttu, S., de Silva, S., 2010. Wetlands, agriculture and poverty

reduction. Colombo, Sri Lanka: International Water Management Institute, pp 39. (IWMI Research Report

137).

— Macfarlane, D., Kotze, D., Ellery, W., Walters, D., Koopman, V., Goodman, P. and Goge, M. 2009.

WET-Health: A technique for rapidly assessing wetland health. Wetland Management Series. Water Research

— Mereta, S.T., Boets, P., Bayih, A. A., Malu, A., Ephrem, Z. Sisay, A., Endale, H., Yitbarek, M., Jemal, A., De Meester, L., Goethals, P. L. M., 2012. Analysis of environmental factors determining the abundance and diversity of macroinvertebrate taxa in natural wetlands of southwest Ethiopia. Ecol Inform7, 52–61. — Mereta S.T., 2013. Water quality and ecological assessment of natural wetlands in Southwest Ethiopia.

PhD thesis, Ghent University, Gent, Belgium.

— Ollis, D., Snaddon, K., Job. N. and Mbona. N. 2013. Classification system for wetland and other aquatic

ecosystems in South Africa. User manual: inland systems. SANBI biodiversity series 22. SANBI Pretoria.

— Seid, G. 2017. Status of Wetland Ecosystems in Ethiopia and Required Actions for Conservation. Journal of Resources Development and Management. 32: 92-100.

— Shewaye, D. 2008. Wetlands and management aspects in Ethiopia: Situation analysis. In the proceedings of the national stakeholders’ workshop on creating national commitment for wetland policy and strategy development in Ethiopia.

— Smith, R.D. A. Amman, C. Bartoldus, and M.M. Brinson. (1995). An approach for assessing wetland

functions using hydrogeomorphic classification, reference wetlands, and functional indices. Technical

Report. WRP-DE-9. U.S. Army Engineer Waterways Experiment Station, Vicksburg, MS.

— Wood, A., 2000. Sustainable Wetland Management in Illubabor Zone, southwest Ethiopia. Policy issues in sustainable wetland management. Ethiopian Wetlands Research Program. Project

B7-6200/96-05/VIII/ENV

— Wolfson, L., Mokma, D., Schultink, G., Dersch, E., 2002. Development and use of a wetlands information