AN ESTIMATION OF WATER AVAILABILITY FROM THE WALVIS …

AN ESTIMATION OF WATER AVAILABILITY FROM THE WALVIS BAY WASTE WATER TREATMENT PLANT FOR USE BY

XARIS ENERGY NAMIBIA

Assessed by: Assessed for:

April 2015

Project: AN ESTIMATION OF WATER AVAILABILITY FROM THE WALVIS

BAY WASTE WATER TREATMENT PLANT FOR USE BY XARIS ENERGY NAMIBIA

Report Version/Date

Final

23 April 2015

Prepared for: Xaris Energy Namibia

Lead Consultant Geo Pollution Technologies (Pty) Ltd

PO Box 11073

Windhoek

Namibia

TEL.: (+264-61) 257411

FAX.: (+264) 88626368

Main Project Team

Pierre Botha (Leader) (B.Sc Geology/Geography); (B.Sc (Hons) Hydrology/Hydrogeology)

Surene Botha (B.Sc Geology); (B.Sc (Hons) Structural Geology); (M.Sc Hydrogeology)

André Faul (B.Sc Zoology/Biochemistry); (B.Sc (Hons) Zoology); (M.Sc Conservation

Ecology)

Cite this document as:

Botha P, Botha S, Faul A; 2015 April; An Estimation of Water Availability from the Walvis Bay Waste Water Treatment Plant for Use by Xaris

Energy Namibia

TABLE OF CONTENTS

1. INTRODUCTION ........................................................................................................................................ 1

2. SCOPE .......................................................................................................................................................... 1

3. BACKGROUND ........................................................................................................................................... 2

3.1. WASTE WATER TREATMENT PLANT .................................................................................................... 2

3.2. WATER REQUIREMENTS ........................................................................................................................ 2

4. POLICY AND LEGAL FRAMEWORK ................................................................................................... 3

4.1. THE CONSTITUTION OF THE REPUBLIC OF NAMIBIA, 1990 ................................................................. 3

4.2. ENVIRONMENTAL MANAGEMENT ACT OF NAMIBIA (2007) ................................................................ 3

4.3. WATER ACT (NO. 54 OF 1956) ............................................................................................................... 3

4.4. WATER RESOURCES MANAGEMENT ACT (ACT NO. 11 OF 2013) (NOT IMPLEMENTED YET) ............. 4

4.5. SOIL CONSERVATION ACT 76 OF 1969 ................................................................................................. 4

4.6. POLLUTION CONTROL AND WASTE MANAGEMENT BILL (GUIDELINE ONLY) .................................... 4

4.7. PUBLIC HEALTH ACT (NO. 36 OF 1919) ................................................................................................ 5

4.8. LOCAL AUTHORITIES ACT, 1992 (ACT NO. 23 OF 1992) ...................................................................... 5

4.9. MUNICIPAL BY-LAWS, GUIDELINES AND REGULATIONS (WALVIS BAY MUNICIPALITY) .................. 5

4.9.1. Integrated Environmental Policy of Walvis Bay (Agenda 21 Project).......................................... 5

4.9.2. Draft Structure Plan of the Municipality of Walvis Bay ............................................................... 6

4.9.3. Sewerage Influent Regulations ..................................................................................................... 6

6. ENVIRONMENTAL CHARACTERISTICS ............................................................................................ 7

6.1. CLIMATE ................................................................................................................................................ 7

6.2. TOPOGRAPHY ......................................................................................................................................... 8

6.3. GEOLOGY AND GEOHYDROLOGY .......................................................................................................... 8

6.4. LAND USE ............................................................................................................................................... 9

7. BIRDS PARADISE .................................................................................................................................... 10

8. WETLAND HISTORIC CHANGES ........................................................................................................ 12

9. WETLAND WATER BALANCE ............................................................................................................. 15

10. WASTE RETURN ................................................................................................................................. 17

11. IDENTIFICATION OF PROJECT KEY RISK AREAS ................................................................... 18

12. IMPACT ASSESSMENT ...................................................................................................................... 19

12.1. METHODOLOGY FOR IMPACT ASSESSMENT ....................................................................................... 19

12.2. REDUCTION IN SIZE OF THE WETLAND .............................................................................................. 20

12.3. MONITORING ....................................................................................................................................... 20

12.4. SALINIZATION OF THE WETLAND ....................................................................................................... 22

12.5. MONITORING ....................................................................................................................................... 22

13. CONCLUSIONS .................................................................................................................................... 24

14. REFERENCES ....................................................................................................................................... 24

Appendix A

BIRD COUNT DATA. .............................................................................................................................. 25

List of Tables

Table 1. Summary of Climate Data ................................................................................................ 7

Table 2. Bird Count Data for the last Two Years ....................................................................... 10

Table 3. Historic Wetland Changes .............................................................................................. 13

Table 4. Factors to be Considered in the Water Balance ........................................................... 16

Table 5: Definitions of each of the Criteria used to determine the significance of impacts ..... 19

Table 6: Definitions of the various significance ratings .............................................................. 20

Table 7. Impact Assessment Reduction in Size of the Wetland....................................................... 21

Table 8. Impact Assessment Salinization of the Wetland ................................................................ 23

List of Figures

Figure 1. Location Map ..................................................................................................................... 1

Figure 2. Flow Diagram indicating Water Volumes, Purification Process and Water Losses ....... 2

Figure 3. Wind Rose for Meersig (Processed Data From Weatherunderground) ......................... 8

Figure 4. Current Land Use Scenario (Urban Dynamics, 2014) ................................................... 9

Figure 5. 2030 Planned Land Use Scenario (Urban Dynamics, 2014) ........................................ 10

Figure 6. Bird Watching Hide Locations ....................................................................................... 11

Figure 7. Historic Wetland Changes .............................................................................................. 14

Figure 8. Conceptual Model ............................................................................................................ 15

Figure 9. Water Supplied to Wetland ............................................................................................ 17

Figure 10. Annual Average Salinity of Influent and Effluent Water (2007 - 2015) (Walvis Bay

Municipality) 18

Figure 11. Current Water Treatment Scenario – Based on 2014 Data ..................................... 18

Figure 12. Planned Water Treatment Scenario – Based on 2014 Data ..................................... 18

Abbreviations

g/cm3 grams per cubic centimetre

km/h kilometre per hour

m metre

m3 cubic metre

m3/d cubic metre per day

m3/h cubic metre per hour

Ma million years

mg/l milligram per litre

mm millimetre

mm/a millimetre per annum

MW mega watt

NACOMA Namibia Coastal Management Project

NOx mono-nitrogen oxides

RO reverse osmosis

TDS total dissolved solids

WAS waste activated sludge

WWTP waste water treatment plant

1. Introduction

Geo Pollution Technologies (Pty) Ltd was appointed by Enviro Dynamics to investigate the possibility

of utilising the semi-purified effluent from the Walvis Bay Waste Water Treatment Plant as a potential

water source for Xaris Energy Namibia’s proposed power plant’s needs at Walvis Bay. Xaris Energy

Namibia has been selected by NamPower to construct and operate a 300 MW power plant to supply

electricity to the national grid. For this purpose, an open cycle gas turbine power plant will be

constructed which will require a significant volume of water for its operational purposes. Purified

sewage effluent water from the Walvis Bay Waste Water Treatment Plant has been identified as a

source of water for the operations of the power plant.

Figure 1. Location Map

2. Scope

The scope of the study is to:

1. Utilise available satellite images to map the extent of the wetland and the changes over time and

compare this with time related water disposal values.

2. Gather historic bird count information. Identify and meet with stakeholders to determine the need

for a wetland and required size.

3. Compile a water balance for the identified wetland area based on existing evaporation and

transpiration data if available. Where a lack of data exist it will be identified and a scope of work

for further studies be compiled. This study will aim at determining the water demand to maintain

the identified wetland area. At this stage it is assumed that the study can be done without hydraulic

conductivity, groundwater- and seawater level data. This data might become necessary if a more

Page 1 of 25

Geo Pollution Technologies (Pty) LtdEstimation of Water Availablility from the Walvis Bay Waste Water Treatment Plant

accurate demand study is required, in which case monitoring boreholes should be drilled and test

pumping measurements obtained.

4. Compile a plan to monitor the wetland to prevent impact on the vegetation and birds due to

insufficient supply of water or salinization of the wetland.

5. Assess the management of waste generated by the demineralisation plant.

3. Background

3.1. Waste Water Treatment Plant At present, the communities of Walvis Bay, Meersig, Kuisebmond and Narraville are serviced

by a water borne network of sewer pipelines. Due to the flat terrain and the fact that the existing

Waste Water Treatment Plant is situated at a higher elevation than the collection network, the

sewage drains under gravity flow to four pumping stations from where it is pumped to the Waste

Water Treatment Plant via four separate pipelines.

At the Waste Water Treatment Plant the sewage is treated to a semi-purified state and part of this

semi-purified water is then used for park and garden watering (irrigation), while the remainder is

disposed of into the dune area southeast of the Waste Water Treatment Plant. This has led to the

establishment of a wetland southeast of the Waste Water Treatment Plant which has also become

an important bird sanctuary. It is sometimes the case that raw sewage enters the wetland,

especially during times of very high effluent flow or when there is a breakdown in the treatment

plant.

3.2. Water Requirements The water required by the power plant will be used for evaporative cooling, for NOx control, for

fire control and as wash water at the power plant. The current estimated water demand for the

power plant is 1,370 m3/d. A demineralisation plant will be constructed at the power plant, located

east of Dune 7 on the Farm 58 industrial park, to clean the effluent to standards suitable for the

power plant’s purposes. With an efficiency of 65% the plant will require an input of 2,797 m3/d

to produce approximately 1,800 m3/d of treated water, assuming the plant runs at 75% capacity.

Untreated sewage water will be pumped to the power plant from the Waste Water Treatment

Plant (WWTP) after being channelled through bioreactor and ultrafiltration stages. At the power

plant water will go through a Reverse Osmosis (RO) process and electro-deionisation process

before being stored for use by the power plant. Waste will be produced in the form of waste

activated sludge (WAS) as well as brine that must be disposed of. See Figure 2 for a diagrammatic

overview of the process.

Figure 2. Flow Diagram indicating Water Volumes, Purification Process and Water Losses

4584 m3/d 2105 m

3/d

TDS: 6112 mg/l TDS: 4931 mg/l

?? m3/d 2479.0 m

3/d 969 m

3/d

TDS: 4931 mg/l TDS Design: 12597 mg/l

TDS Expected: 4622 mg/l

28.0 m3/d

2797 m3/d 2769 m

3/d 1800 m

3/d

TDS Design: 4409 mg/l


WAS Rate: 1% RO Recovery: 65%

Located at WWTP Located at Power Plant

To

Turbines

Reverse

Osmosis

Ultra

Filtration

Bio-

reactor

Electro

Deionisation

Brine to

Disposal

WAS to

Disposal

WWTP Feed WWTP Wetland

Disposal

Irrigation

Page 2 of 25


4. Policy and Legal Framework

This section presents an overview of the most relevant legislation related to Ground and Surface water

with the aim of informing the applicant of the legal requirements pertaining to the project for all phases

of development.

4.1. The Constitution of the Republic of Namibia, 1990 Article 95 of Namibia’s constitution provides that:

“The State shall actively promote and maintain the welfare of the people by adopting, inter alia,

policies aimed at the following:

(l) management of ecosystems, essential ecological processes and biological diversity of Namibia

and utilization of living natural resources on a sustainable basis for the benefit of all Namibians,

both present and future; in particular the Government shall provide measures against the

dumping or recycling of foreign nuclear and toxic waste on Namibian territory.”

This article recommends that a relatively high level of environmental protection is called for in

respect of groundwater utilization, management, pollution control and waste management.

4.2. Environmental Management Act of Namibia (2007) The Act provides a broad definition to the term “environment” - land, water and air; all organic

and inorganic matter and living organisms as well as biological diversity; the interacting natural

systems that include components referred to in sub-paragraphs, the human environment insofar

as it represents archaeological, aesthetic, cultural, historic, economic, palaentological or social

values.

4.3. Water Act (No. 54 of 1956)

The purpose of the Act is “to consolidate and amend the laws relating to the control, conservation

and use of water for domestic, agricultural, urban and industrial purposes; to make provision for

the control, in certain respects, of the use of sea water for certain purposes; for the control of

certain activities on or in water in certain areas; for the control of activities which may alter the

natural occurrence of certain types of atmospheric precipitation; for the control, in certain

respects, of the establishment or the extension of townships in certain areas; and for incidental

matters.” It further controls the disposal of effluent.

The Act makes it a criminal offence to:

“Pollute fresh water or the sea in a way that makes the water less fit for any purpose for which

it is or could be used by people, including use for the propagation of fish or other aquatic life, or

use for recreational or other legitimate purpose.”

This Act requires that water used for industrial purposes be purified before it is returned to a

public stream or the sea, so as to conform with requirements (General Standard Quality

restrictions as laid out in Government Gazette R553 of 5 April 1962) established by the Minister

of Agriculture, Water and Rural Development, but can be exempted from doing so, subject to

certain conditions. The Minister may issue a permit to allow the discharge of waste water, effluent

or waste in an un-purified or semi-purified state into a public stream, subject to such conditions

that it does not cause pollution of “public or other water, including sea water” or provided that

the discharge point is sufficiently close to the sea that no person will be prejudicially, and no

aquatic or marine life detrimentally, affected by such discharge.

Page 3 of 25


TABLE 5 GENERAL STANDARDS FOR ARTICLE 21 PERMITS (EFFLUENTS)

Arsenic 0.5 mg/l as As

Biological Oxygen Demand (BOD) no value given

Boron 1.0 mg/l as B

Chemical Oxygen Demand (COD) 75 mg / l as O

Chlorine, residual 0.1 mg/l as Cl2

Chromium, hexavalent 50 μg/l as Cr(VI)

Chromium, total 500 μg/l as Cr

Copper 1.0 mg/l as Cu

Cyanide 500 μg/l as CN

Oxygen, Absorbed (OA) 10 mg / l as O*

Oxygen, Dissolved (DO) at least 75% saturation**

Detergents, Surfactants, Tensides 0.5 mg/l as MBAS

Fats, Oil & Grease (FOG) 2.5 mg/l (!gravimetric method)

Fluoride 1.0 mg/l as F

Free & Saline Ammonia 10 mg/l as N

Lead 1.0 mg/l as Pb

pH 5.5 – 9.5

Phenolic Compounds 100 μg/l as phenol

Phosphate 1.0 mg/l as P

Sodium not more than 90 mg/l Na more than influent

Sulphide 1.0 mg/l as S

Temperature 35°C

Total Dissolved Solids (TDS) not more than 500 mg /l more than influent

Total Suspended Solids (TSS) 25 mg/l

Typical faecal Coli. no typical coli should be counted per 100 ml

Zinc 5.0 mg/l as Zn

* Also known as Permanganate Value (or PV).

** In Windhoek the saturation level is at approx. 9 mg/l O2.

4.4. Water Resources Management Act (Act No. 11 of 2013) (Not implemented yet) The Act aims to provide management of the national water resources to achieve sustainable use

of water for the benefit of all water users. This requires that the quality of water resources is

protected as well as integrated management of water resources with the delegation of powers to

institutions at the regional or catchment level.

The purpose of this Act is to broadly control the use and conservation of water for domestic,

agricultural, urban and industrial purposes; to control, in certain respects, the use of sea water; to

control certain activities on or in water in certain areas; and to control activities which may alter

the natural occurrence of certain types of atmospheric precipitation.

4.5. Soil Conservation Act 76 Of 1969

The Act aims to consolidate and amend the law relating to the combating and prevention of soil

erosion, the conservation, improvement and manner of use of the soil and vegetation and the

protection of the water sources in the Republic and the territory of South-West Africa; and to

provide for matters incidental thereto.

4.6. Pollution Control and Waste Management Bill (guideline only)

Part 7 states that any person who sells, stores, transports or uses any hazardous substances or

products containing hazardous substances shall notify the competent authority, in accordance

with sub-section (2), of the presence and quantity of those substances.

Page 4 of 25


The competent authority for the purposes of section 74 shall maintain a register of substances

notified in accordance with that section and the register shall be maintained in accordance with

the provisions.

Part 8 provides for emergency preparedness by the person handling hazardous substances,

through emergency response plans.

4.7. Public Health Act (No. 36 of 1919) Section 111 it is the duty of every local authority to take all lawful, necessary and reasonably

practical measures for preventing the pollution so as to endanger health of any supply of water

within its district and to take measures against any person so polluting any such supply.

Section 119 states that no person shall cause a nuisance or shall suffer to exist on any land or

premises owned or occupied by him or of which he is in charge any nuisance or other condition

liable to be injurious or dangerous to health.

Section 132 empowers the Minister to make regulations regarding, inter alia, the drainage of land

or premises, the disposal of liquids and the removal and disposal of rubbish, refuse, manure and

waste matters as well as regarding the establishment and carrying on of factories or trade premises

which are liable to cause offensive smells or effluvia or to discharge liquid or other material liable

to cause such smells or effluvia or to pollute streams and prohibiting the establishment or carrying

on of such factories in unsuitable localities.

4.8. Local Authorities Act, 1992 (Act No. 23 of 1992)

The Act aims to provide for the determination, for purposes of local government, of local

authority councils; the establishment of such local authority councils; and to define the powers,

duties and functions of local authority councils; and to provide for incidental matters.

This act prohibits, without municipal approval, the discharge into the sewer system of the

following:

� any gas or steam;

� any liquid other than domestic waste water of a temperature higher than 40 degrees Celsius;

� any petrol or oil or substances containing petrol or oil;

� any liquid refuse from any abattoir;

� any chemical refuse;

� any industrial, trade or manufacturing waste.

Section 94(1) of the Local Authorities Act, 1992, empowers the local authority, after consultation

with the Minister responsible for local government, to promulgate regulations in relation to, the

supply, distribution and use of water in its local authority area, including the protection of water

from pollution.

4.9. Municipal By-laws, Guidelines and Regulations (Walvis Bay Municipality)

4.9.1. Integrated Environmental Policy of Walvis Bay (Agenda 21 Project) The Integrated Environmental Policy indicates the directions that the Municipality of Walvis

Bay will move towards in the forthcoming years to fulfil its responsibilities to manage the

environment of Walvis Bay together with the town’s residents and institutions.

It is a statement of purpose that commits the municipality to certain principles, policy

directions, and tools. It serves as an adaptive, flexible framework for a series of sectoral

strategies and action plans, these inspired by visions of a better environmental future.

The Policy is directed at assuring the longer-run management of Walvis Bay’s environment

for the benefit of all its residents and its visitors.

The policy has identified ten (10) priority areas that need to be tackled by the Municipality,

these are:

Page 5 of 25


� Managing Walvis Bay’s Ramsar Wetland Site

� Minimising the Consumption of Water

� Reducing Marine Pollution in Walvis Bay itself

� Improving Walvis Bay’s Air Quality

� Understanding and Solving Ground Pollution Issues

� Conserving Threatened Species and their Habitats

� Managing Off-Road Driving and other Recreational Activities

� Improving Sanitation Facilities for Shack Dwellers

� Eradicating Litter Hotspots in Walvis Bay and on the Seashore

� Educating Residents, particularly Learners, about Walvis Bay’s Environment and its

Ecosystems.

4.9.2. Draft Structure Plan of the Municipality of Walvis Bay The main objective of the Structure Plan is “to Set Guidelines that will ensure the best possible

living conditions and environment for the residents of Walvis Bay.” The secondary goals and

objectives of the Structure Plan are as follows:

� “Provide sufficient infrastructure to all erven;

� Lessen the shortage in housing and accommodation; and

� Establish and develop a diversified economic base by looking at tourism, manufacturing,

fishing, services and sectors and the port/harbour for example”

4.9.3. Sewerage Influent Regulations The Walvis Bay Municipality does not provide specific limits as to allowable discharges into

the sewerage system. Since no separate industrial sewage treatment plant exists the guidelines

of the Local Authorities Act (Act 23 of 1992) should be followed.

The Walvis Bay Municipality further applies the Drainage and Plumbing By-Law of 1958

(updated in 1982), which states:

“If it is ascertained that the introduction into a municipal sewer of any solid matter,

suspended matter, mud, chemical or manufacturing or trade or other refuse (inclusive of

vapours or gaseous matters) or of any steam, condensing water, heated waters or other liquid

(such water or other liquid being of a higher temperature than 110 degrees Fahrenheit

[43.33°C]), whether alone or in combination with other matter or liquids, and whether

directly or through any drain or channel communicating with such sewer, either does, or may

cause a nuisance, or involve danger to health of persons entering the sewers, or others, or is

or may be injurious to the structure of materials of the sewers or works of the Council, or to

any ground used by the Council for the disposal of sewage, the Council may, by order,

absolutely prohibit from a date to be named in such order, not being earlier than 14 days from

service of such order, any such matter or matters being caused or permitted to fall, flow or

enter, or to be carried or washed into any sewer either directly or indirectly.”

The Walvis Bay Municipality is in the process of updating the Drainage and Plumbing By-

Law of 1958 (updated in 1982) and this should be promulgated in the near future. It is Xaris’s

responsibility to familiarize themselves with the details once promulgated and to adhere to

any regulations applicable to their Facility in Walvis Bay.

Page 6 of 25


6. Environmental Characteristics

This section describes the general environmental conditions of the area.

6.1. Climate

Walvis Bay is centrally located on the Namibian coastline in the arid Namib Desert. The arid

conditions are as a result of dry descending air and upwelling of the cold Benguela Current. Thick

fog or low stratus clouds are a regular occurrence in Walvis Bay. This is due to the influence of

the Benguela Current and forms the major source of water for the succulent and lichen flora in

the Namib Desert.

Namibia is situated within an anti-cyclone belt of the Southern Hemisphere. Winds generated

from the high-pressure cell over the Atlantic Ocean blow from a southerly direction when they

reach the Namibian coastline. As the Namibian interior is warm (particularly in summer),

localised low-pressure systems are created which draws the cold southerly winds towards the

inland desert areas. These winds manifest themselves in the form of strong prevailing south-

westerly winds, which range from an average of 20 knots (37 km/h) during winter months to as

high as 60 knots (110 km/h) during the summer. Wind conditions in Walvis Bay is presented in

a series of wind roses in Figure 3. During winter, the east winds generated over the hot Namib

Desert have a strong effect on temperature, resulting in temperature in the upper 30’s degrees

Celsius and tend to transport plenty of sand.

Table 1 presents a summary of climate conditions in the Walvis Bay area.

Table 1. Summary of Climate Data

Average annual rainfall (mm/a) 0-50

Variation in annual rainfall (%) < 100

Average annual evaporation

(mm/a)

2400-2600

Water deficit (mm/a) 1701-1900

Temperature Average maximum: Between 24°C in March/April and 19.3°C in

September

Average minimum: Between 16.5°C in February and 9.1°C in

August

Average annual >16°C

Fog Approximately 900 hours of fog per year

Wind Prevailing wind is average to strong south westerly (See Figure 3

for Wind Rose plot of data from Meersig ERONGO3)

Page 7 of 25


Figure 3. Wind Rose for Meersig (Processed Data From Weatherunderground)

6.2. Topography

The topography in Walvis Bay is generally flat with a local gentle slope in a westerly direction

(towards the harbour). Drainage is poorly developed due to the lack of rainfall (<50 mm/annum)

received in the area. The western part of the area of interest is relatively flat with dunes becoming

more prominent to the east. Dune movement is taking place in a northeasterly direction.

6.3. Geology and Geohydrology

Walvis Bay is a coastal town in the very old and dry Namib Desert. The surrounds is dominated

by shifting sand dunes and rolling hills with the elevation remaining below 100 m above sea

level. Further inland is the gravel plains of the central areas of the Namib Naukluft Park. Surface

water around Walvis Bay is limited to the marine salt pans, lagoon and ocean as well as a man-

made wetland formed as a result of the waste water treatment Plant.

Walvis Bay is located in the Central Western Plain of Namibia. The Kuiseb River forms the

southern boundary of this landscape group, with the Namib Dune Field being present south of

the Kuiseb River. Northerly dune migration is forcing the Kuiseb River in a northerly direction,

with Kuiseb River paleochannels being present as far south as Sandwich Harbour.

Following the breakup of West-Gondwana during the early Cretaceous (130 – 135 Ma ago),

continental uplift took place, enhancing erosional cutback and the formation of the Namibian

Escarpment. A narrow pediplain formed, mainly over Damara Age Rocks. The South Atlantic

started filling in over the pediplain, with marine conditions established around 80Ma ago.

Towards the end of the Cretaceous (70 – 65 Ma ago) a relative level surface was created, on

which later deposition of sediments took place. Marine deposition took place in the parts covered

by the newly formed South Atlantic Ocean, while terrestrial deposits took place on land. Further

continental uplift moved the shoreline to its present position.

Northwards migration of sand covered parts of the exposed marine deposits, with Kuiseb floods

also depositing material over the marine sediments. Depth to bedrock in Walvis Bay is expected

to be deeper than 40m. Based on previous work conducted in the area it is expected that the

sediments under the project area would consist of medium to coarse grain sand with thin lenses

Page 8 of 25


of more clayey material and layers of shell material. The hydraulic conductivity is expected to be

moderate to high.

Groundwater is not abstracted for human consumption in Walvis Bay. The Municipality of

Walvis Bay currently purchase fresh/potable water from NamWater, which source water from

the Kuiseb Water Supply Scheme.

6.4. Land Use In the Integrated Spatial Development Framework for Walvis Bay (Urban Dynamics, 2014) the

planned land use for Walvis Bay is defined. Figure 4 and Figure 5 presents the current land use

scenario and the 2030 land use scenario respectively. In Figure 5 it is clear that the plan makes

provision for the wetland in 2030, but that the wetland will be boxed in by development, leaving

little room for future expansion. It is therefore important that the future growth of water

discharged into the wetland be managed and probably be reduced to limit further growth of the

size of the wetland.

Wetland

Figure 4. Current Land Use Scenario (Urban Dynamics, 2014)

Page 9 of 25


Wetland

City Park

Regional Shopping Centre

Industrial

Urban Agriculture

City Sports Ground

Figure 5. 2030 Planned Land Use Scenario (Urban Dynamics, 2014)

7. Birds Paradise

The Walvis Bay Bird Paradise facility established in 2013 offers guided birding walks through the

wetland. Namibia Coastal Management Project (NACOMA), the Municipality of Walvis Bay and the

Ministry of Environment and Tourism funded and/or supported the facility. Various hides were planned

in 2013 (ref: Birds Paradise Guide) to expand the bird viewing facilities throughout the wetland, see

Figure 6. It however seems as if only 2 were constructed and both were destroyed by strong wind.

Bird counts are regularly conducted throughout the wetland and thousands of birds are reportedly

supported at any given time. However, significant variability also exists in the number of birds counted

at the wetlands although the number of different species remains relatively constant (see Table 2).

Among the approximately 30 species of birds making use of the wetlands, 5 are near-threatened with

one of those being threatened globally. One species is a southern African endemic. Appendix A provides

detailed information on the last winter and summer bird counts. The wetland provides protection against

the wind and predators, but also supplies food to the birds. Any changes to the extent of the wetlands

will impact on bird numbers, the amount of food available for the birds and nesting habitat for resident

bird species.

Table 2. Bird Count Data for the last Two Years

Date Number of Species Total Number of Birds

July 2013 32 16,159

February 2014 29 7,576

July 2014 29 4,294

February 2015 30 9,842

Page 10 of 25


Figure 6. Bird Watching Hide Locations

Page 11 of 25


Photo 1. Channel to the southeast

Photo 2. Pond with no vegetation

Photo 3. First vegetation

Photo 4. Denser vegetation

Photo 5. Dense vegetation

Photo 6. Birds

8. Wetland Historic Changes

The wetland was originally located just southeast of the traffic circle as one enters Walvis Bay from

Swakopmund, see July 2004 in Figure 7. Due to mosquito and smell issues it was decided to push the

wetland further away by digging a trench to channel the flow of water further southeast. The effect can

be seen in Figure 7 which presents a series of historic satellite images (Google Earth), on which the

vegetated areas and open water areas were mapped. This data is summarised in Table 3.

Initially an increase in the wetland area took place as larger areas were supplied with fresh water. Due

to the relative rapid rate that the water was forced further southeast, the reeds to the west died as the

supply of freshwater diminished, while a relative large water body developed to the southeast. The area

to the southeast has much more dune coverage than the western original area. This had the effect that

saturated conditions developed underneath the dunes with water pools between the dunes. Vegetation

Page 12 of 25


was only able to grow around these pools with the rapid change in depth to the water due to dune

topography limiting the development of vegetation higher up on the dunes.

Table 3. Historic Wetland Changes

Date Vegetated Area

(m2)

Water Area

(m2)

Total Area

(m2)

2004 437, 679 97,626 535,306

2007 647,535 123,229 770,764

2011 289,849 315,818 605,668

2013 432,202 392,602 824,804

2015 400,000 371,583 771,583

Page 13 of 25


Figure 7. Historic Wetland Changes

Page 14 of 25


9. Wetland Water Balance

A unique hydrogeological environment to Namibia presents itself in the wetlands of Walvis Bay. As

fresh water is continuously released into the dune area, a freshwater lens has formed on top of the saline

water. This hydrogeological phenomenon can be better explained by the Ghyben-Herzberg relation

(Langevin, 1998).

Figure 8. Conceptual Model

The Ghyben-Herzberg relation is formulated as follows:

hzfs

f

)( ρρ

ρ

−=

where the thickness of the fresh water zone above the saline water level is represented as h and the

saline water thickness is represented as z. The two thicknesses h and z, are related by fρ and sρ where

fρ is the density of freshwater and sρ is the density of saline water.

The Ghyben-Herzberg relation refers to the interaction of fresh and saline water. Fresh water has a

density of 1.0 g/cm3 at 20 °C and saline water (seawater in this case) has a density of 1.025 g/cm3 at 20

°C. Therefore the less dense fresh water will “float” on top of the denser saline water and create a fresh

water lens.

The ratio of fresh water on top of saline water can be postulated as for every one unit of fresh water in

an unconfined aquifer above the saline water level, there will be forty units of fresh water in the aquifer

below the saline water level.

Based on the assumption that the area is underlain by saline water, it is therefore proposed that a fresh

water lens was created by the release of fresh water into the dune area. The fresh water is buffered by

the underlying saline water and thus created the wetlands known as Birds Paradise. This however is a

phenomenon that only exists because of the release of fresh water and the Ghyben-Herzberg relation

thereof to the saline water underneath.

Page 15 of 25


For the scope of this study, it is hypothesised that the saline water confines the fresh water and that the

fresh water lens has been established and is stable. A water balance is a mathematical summary of all

the relevant factors keeping the system in equilibrium. For the scope of this project, the main factors to

be considered in the water balance are presented in Table 4.

Table 4. Factors to be Considered in the Water Balance

Factor Estimated quantity Significance Literature

In-flux:

Semi treated effluent

from the Waste Water

Treatment Plant

4,902 m3/day

Average 2014

Significant Data supplied by WVB

Municipality, see

Appendix A for table

Precipitation 0 – 50 mm/a Insignificant Mendelsohn T, et al;

2002

Out-flux:

Evapotranspiration

(inclusive of open

water bodies and

vegetation)

4 mm/day Significant Mendelsohn T, et al;

2002

Seepage 0 – 9.2 mm/day Insignificant – the

fresh water lens is

already established and

stable.

Lyngus H; 2003

A total wetted area for January 2015 of approximately 771,583 m2 was calculated for the project, based

on historic satellite images, see Figure 7. Based on the available information the formula for the wetland

water balance is postulated as;

QTotal = QIn – OOut

Where

QTotal = the deficit of the water balance,

QIn = total in-flux (semi-purified effluent + precipitation)

QOut = total out-flux (evapotranspiration + seepage)

Thus

QTotal = QIn – OOut

= [4,902 m3/day + 0] – [(771,583 m2 x 4 mm/day) + 0]

= [4,902 m3/day] – [3,086 m3/day + 0]

= 1,186 m3/day

The positive figure of 1,186 m3/day indicates that the wetland should be growing. From Table 3 it seems

as if there is a slight decrease in the size of the wetland between 2013 and 2015, despite the increase in

water released to the wetland, see Figure 9. It is interpreted that the water is spreading more under the

dune area and less water is therefore exposed. The freshwater lens will however still expand but will

not be visually identified under the dune area.

From the water balance it is evident that only 1,186 m3/day semi-purified water is available for other

projects, if the current wetland area is to be sustained. Reduced water supply to the wetland, or

abstraction from the wetland will cause a decrease in the two thicknesses h and z and in the lateral extent

of the freshwater body.

Figure 9 presents the historic data of water pumped to the wetland as well as the impact on this volume

that would take place if Xaris diverts 2,151 m3/d from the system and return 745 m3/d of brine to the

wetland.

Page 16 of 25


Figure 9. Water Supplied to Wetland

10. Waste Return

Figure 10 presents average annual influent and effluent TDS values, as based on information supplied

by the Walvis Bay Municipality. Figure 11 presents a mass balance of the current waste water treatment

scenario as based on average values for 2014.

For the Xaris plant it is estimated that 2,797 m3/d of influent water will be diverted away from the Waste

Water Treatment Plant to a bioreactor from where it will pass through an ultrafiltration process before

reverse osmosis will take place to reduce the TDS of the water. The bioreactor and ultrafiltration process

will produced approximately 28 m3 activated sludge waste per day, while the reverse osmosis process

will produce approximately 969 m3 brine per day that must be disposed of.

The activated sludge will be returned to the existing Waste Water Treatment Plant. Waste water from

the reverse osmosis process will be returned to the wetland area. Figure 12 presents a mass balance

calculation for the current waste water treatment scenario as based on average values for 2014,

combined with the planned Xaris setup. It is estimated that the combined discharge to the wetland will

have a TDS of approximately 7,348 mg/l. This is approximately 3,791 mg/l higher than the 2014

average of 3,557 mg/l, which is a doubling in the discharge TDS.

The volume of water discharge to the wetland will reduce with 1,828 m3/h from 4,902 m3/h to 3,074

m3/h. It is expected that the increased salt loading coupled with reduced water discharge volumes will

cause a risk of salinization of the wetland.

Page 17 of 25


Figure 10. Annual Average Salinity of Influent and Effluent Water (2007 - 2015) (Walvis Bay Municipality)

Figure 11. Current Water Treatment Scenario – Based on 2014 Data

Figure 12. Planned Water Treatment Scenario – Based on 2014 Data

11. IDENTIFICATION OF PROJECT KEY RISK AREAS

The main risk areas is the reduction in size of the wetland and the possible salinization of the wetland.

Both risk areas are associated with an impact on the bird life, vegetation and the Birds Paradise Tourism

sector.

Current Scenario

Final TDS

7381 m3/d 4902 m

3/d 3557 mg/l


?? m3/d 2479.0 m

3/d

TDS: 3557 mg/l


Disposal

Irrigation

WAS to

Disposal

Planned Scenario

Final TDS

4584 m3/d 2105 m

3/d 7348 mg/l


?? m3/d 2479.0 m

3/d 969 m

3/d

TDS: 4931 mg/l TDS Design: 12597 mg/l


28.0 m3/d

2797 m3/d 2769 m

3/d 1800 m

3/d

TDS Design: 4409 mg/l


WAS Rate: 1% RO Recovery: 65%

Located at WWTP Located at Power Plant

To

Turbines

Reverse

Osmosis

Ultra

Filtration

Bio-

reactor

Electro

Deionisation

Brine to

Disposal

WAS to

Disposal


Disposal

Irrigation

Page 18 of 25


12. IMPACT ASSESSMENT

12.1. Methodology for Impact Assessment In accordance with the requirements of the EIA process, the potential impacts identified as part

of the assessment has to be evaluated to determine the significance of each impact and anticipated

severity of the impact on the surrounding environment.

The methodology whereby the significance of each impact is evaluated, include the following

variables (evaluation components):

1. Extent (spatial scale);

2. Duration (time scale);

3. Probability of occurrence; and

4. Intensity or magnitude of the impact.

The evaluation proceeds by ranking identified impacts in terms of a scale of severity for each

evaluation component as presented in Table 5.

Table 5: Definitions of each of the Criteria used to determine the significance of impacts

Description

Nature Reviews the type of effect that the proposed activity will have on the relevant

component of the environment and includes “what will be affected and how?”

Extent Geographic area. Indicates whether the impact will be within a limited area (on

site where construction is to take place); local (limited to within 15km of the

area); regional (limited to ~100km radius); national (limited to the coastline of

Namibia); or international (extending beyond Namibia’s boarders).

Duration Whether the impact will be temporary (during construction only), short term (1-

5 years), medium term (5-10 years), long term (longer than 10 years, but will

cease after operation) or permanent.

Intensity Establishes whether the magnitude of the impact is destructive or innocuous and

whether or not it exceeds set standards, and is described as none (no impact); low

(where natural/ social environmental functions and processes are negligibly

affected); medium (where the environment continues to function but in a

noticeably modified manner); or high (where environmental functions and

processes are altered such that they temporarily or permanently cease and/or

exceed legal standards/requirements).

Probability Considers the likelihood of the impact occurring and is described as uncertain,

improbable (low likelihood), probable (distinct possibility), highly probable

(most likely) or definite (impact will occur regardless of prevention measures).

Significance Significance is given before and after mitigation. Low if the impact will not have

an influence on the decision or require to be significantly accommodated in the

project design, Medium if the impact could have an influence on the environment

which will require modification of the project design or alternative mitigation

(the route can be used, but with deviations or mitigation) High where it could

have a “no-go” implication regardless of any possible mitigation (an alternative

route should be used).

Status of the impact

A statement of whether the impact is positive (a benefit), negative (a cost), or

neutral. Indicate in each case who is likely to benefit and who is likely to bear

the costs of each impact.

Degree of

Confidence in Predictions

Is based on the availability of specialist knowledge and other information.

Page 19 of 25


The application of the above criteria to determine the significance of potential impacts uses a

balanced combination of duration, extent, and intensity/magnitude, modified by probability,

cumulative effects, and confidence. Significance is described as follows:

Table 6: Definitions of the various significance ratings

SIGNIFICANCE RATING

CRITERIA

Low Where the impact will have a negligible influence on the environment and

no modifications or mitigations are necessary for the given development

description. This would be allocated to impacts of any severity/

magnitude, if at a local scale/ extent and of temporary duration/time.

Medium Where the impact could have an influence on the environment, which will

require modification of the development design and/or alternative

mitigation. This would be allocated to impacts of medium

intensity/magnitude, locally to regionally, and in the short term.

High Where the impact could have a significant influence on the environment

and, in the event of a negative impact the activity(ies) causing it, should

not be permitted (i.e. there could be a ‘no-go’ implication for the

development, regardless of any possible mitigation). This would be

allocated to impacts of high magnitude, locally for longer than a month,

and/or of high magnitude regionally and beyond.

12.2. Reduction in Size of the Wetland The current wetland size extend outside of the 2030 structural plan for the wetland, meaning that

the wetland is larger than what the town planers would want it to be, see Figure 5. There is

therefore a desire to reduce the size of the wetland. A business, supported by the Walvis Bay

Municipality and by NACOMA was establish that rely on the wetland, specific on the abundance

of birds related to the wetland.

It should be kept in mind that the effluent volumes discharged into the wetland is growing (see

Figure 9), while the Municipality is planning to reduce the actual size of the wetland. It is

therefore important that the Municipality start diverting water away from the wetland in a

controlled manner.

The impacts caused by the reduction in the size of the Wetland is presented in Table 7.

12.3. Monitoring

Monitoring holes should be installed to monitor fluctuations in the saline water and freshwater

levels over time. Placement of the monitoring holes must be based on the 2030 structural plan of

the area. The monitoring data should provide for an early warning system to minimise the impact

on the vegetation and ponds. It will also provide much needed information to better optimise the

amount of water supplied to the wetland.

Monthly monitoring of the monitoring hole water levels (freshwater and freshwater / saline water

interface) and of the volume of semi-purified effluent released to the wetlands will be required

to determine the long-term impact of fluctuating releases on the wetlands, as well as to better

understand and improve the water balance. Visual inspection of the state of the vegetation must

be conducted every 6 months and compared with the extend of the wetland.

A baseline of the Birds Paradise financial situation must be set prior to reduction in the wetland

size. The financial situation must then be evaluated during the reduction in size of the wetland on

a yearly base.

Page 20 of 25


Tab

le 7

. Im

pact

Ass

essm

ent

Red

uct

ion

in

Siz

e of

the

Wet

lan

d

PO

TE

NT

IAL

IM

PA

CT

S

TA

TU

S/

NA

TU

RE

E

XT

EN

T

DU

RA

TIO

N

INT

EN

SIT

Y

PR

OB

AB

ILIT

Y

DE

GR

EE

O

F

CO

NF

IDE

NC

E

SIG

NIF

ICA

NC

E

PR

E-

MIT

IGA

TIO

N

MIT

IGA

TIO

N/

EN

HA

NC

EM

EN

T

PO

ST

-

MIT

IGA

TIO

N

OP

ER

AT

ION

AN

D M

AIN

TE

NA

NC

E P

HA

SE

Veg

etati

on

Dy

ing

neg

ativ

e

loca

l lo

ng

hig

h

pro

bab

le

hig

h

med

ium

S

om

e veg

etat

ion

dyin

g o

ff

can

b

e ex

pec

ted

as

th

e

wet

lan

d w

ill

be

red

uce

d i

n

size

. It

is

ho

wev

er im

po

rtan

t

that

th

is

on

ly

take

pla

ce

ou

tsid

e th

e 20

30

p

lan

ned

bo

un

dar

ies.

low

Red

uce

d

po

nd

siz

e

neg

ativ

e

loca

l lo

ng

hig

h

pro

bab

le

hig

h

med

ium

S

om

e re

du

ctio

n in p

ond

siz

e

be

exp

ecte

d a

s th

e w

etla

nd

wil

l b

e re

du

ced

in

siz

e. I

t is

ho

wev

er i

mp

ort

ant

that

th

is

on

ly t

ake p

lace

ou

tsid

e th

e

20

30

pla

nn

ed b

ou

nd

arie

s.

low

Imp

act

on

B

ird

s P

ara

dis

e

Bu

sin

ess

Case

neg

ativ

e

loca

l lo

ng

hig

h

pro

bab

le

hig

h

med

ium

T

he

curr

ent fe

asib

ilit

y o

f th

e

Bir

ds

Par

adis

e B

usi

nes

s

seem

s q

ues

tio

nab

le.

It

is

ho

wev

er

imp

ort

ant

that

a

bas

elin

e b

e se

t p

rio

r to

th

e

red

uct

ion

o

f si

ze

of

the

wet

lan

d

to

avo

id

futu

re

clai

ms.

C

oop

erat

ion

wit

h

the

bu

sin

ess

to i

mp

rove

the

curr

ent

bu

sin

ess

case

ca

n

po

ssib

ly

enh

ance

th

e

bu

sin

ess.

low

DE

CO

MM

ISS

ION

ING

PH

AS

E

Flo

od

ing

of

are

as

ou

tsid

e th

e 2

030

pla

nn

ed

bo

un

dari

es

neg

ativ

e

loca

l lo

ng

hig

h

pro

bab

le

hig

h

med

ium

T

he

Mu

nic

ipal

ity n

eed

s to

hav

e a

con

tin

gen

cy p

lan

in

pla

ce t

o m

anag

e d

isp

osa

l o

f

wat

er

into

th

e w

etla

nd

if

Xar

is

wil

l no

lo

nger

ta

ke

wat

er f

rom

th

e sy

stem

.

low

Page 21 of 25


12.4. Salinization of the Wetland It is estimated that the combined discharge from the WWTP and Xaris brine to the wetland will

have a TDS of approximately 7,348 mg/l. This is approximately 3,791 mg/l higher than the 2014

average of 3,557 mg/l, which is a doubling in the discharge TDS.

The volume of water discharge to the wetland will reduce with 1,828 m3/h from 4,902 m3/h to

3,074 m3/h. It is expected that the increased salt loading coupled with reduced water discharge

volumes will cause a risk of salinization of the wetland. Typical impacts expected from this risk

is further dying of vegetation and relocation of the freshwater birds depending on the wetland.

The process of assessing the significance of each of the possible impacts is contained in Table 8.

12.5. Monitoring Monitoring holes should be installed to monitor fluctuations in the saline water and freshwater

levels. Placement of the monitoring holes must be based on the 2030 structural plan of the area.

The monitoring data should provide for an early warning system to minimise the impact on the

vegetation and ponds. It will also provide much needed information to better optimise the amount

of water supplied to the wetland.

Monthly TDS monitoring of the monitoring hole water and the semi-purified effluent released to

the wetlands will be required to determine the long-term impact of fluctuating releases on the

wetlands, as well as to better understand and improve the water balance. Visual inspection of the

salt deposits and of the state of the vegetation must be conducted every 6 months and compare to

changes in water salinity.

Page 22 of 25


Tab

le 8

. Im

pact

Ass

essm

ent

Sali

niz

ati

on

of

the

Wet

lan

d

PO

TE

NT

IAL

IM

PA

CT

S

TA

TU

S/

NA

TU

RE

E

XT

EN

T

DU

RA

TIO

N

INT

EN

SIT

Y

PR

OB

AB

ILIT

Y

DE

GR

EE

O

F

CO

NF

IDE

NC

E

SIG

NIF

ICA

NC

E

PR

E-

MIT

IGA

TIO

N

MIT

IGA

TIO

N/

EN

HA

NC

EM

EN

T

PO

ST

-

MIT

IGA

TIO

N

OP

ER

AT

ION

AN

D M

AIN

TE

NA

NC

E P

HA

SE

Veg

etati

on

Dy

ing

neg

ativ

e

loca

l lo

ng

hig

h

pro

bab

le

hig

h

med

ium

S

om

e veg

etat

ion

dyin

g o

ff

can

b

e ex

pec

ted

as

th

e

wet

lan

d w

ill

be

red

uce

d i

n

size

. It

is

ho

wev

er im

po

rtan

t

that

th

is

on

ly

take

pla

ce

ou

tsid

e th

e 20

30

p

lan

ned

bo

un

dar

ies.

If

sa

lin

izat

ion

bec

om

es

a p

rob

lem

inves

tigat

e to

d

iver

t th

e

Bri

ne

dis

po

sal

to t

he

Oce

an

low

Fre

shw

ate

r B

ird

s

Rel

oca

tin

g

neg

ativ

e

loca

l lo

ng

hig

h

pro

bab

le

hig

h

med

ium

S

om

e re

du

ctio

n in p

ond

siz

e

be

exp

ecte

d a

s th

e w

etla

nd

wil

l b

e re

du

ced

in

siz

e. I

t is

ho

wev

er i

mp

ort

ant

that

th

is

on

ly t

ake p

lace

ou

tsid

e th

e

20

30

pla

nn

ed b

ou

nd

arie

s. I

f

sali

niz

atio

n

bec

om

es

a

pro

ble

m

inves

tigat

e to

div

ert

the

Bri

ne

dis

po

sal

to

the

Oce

an

low

Page 23 of 25


13. Conclusions

It is considered possible to obtain the required volume of water from the Waste Water Treatment

process, as proposed in this document. Care should however be taken initially that the size of the wetland

is not reduced at a too rapid pace. Over time the impact of the water abstraction by Xaris will become

less as the expected growth of the town increase, with an associated increase in sewage volumes.

The salinization of the wetland is a concern and careful monitoring is called for to identify potential

salinization impacts. If salinization becomes a problem, then the alternative brine disposal into the ocean

should be investigated.

Other concerns is that if the better influent quality streams are diverted to the Xaris plant, then the

WWTP of the Municipality will have to deal with higher TDS influent. This might make the WWTP

less efficient initially until the micro-organism manage to adapt to the changing TDS. A higher TDS

influent into the WWTP will further result in higher TDS irrigation water that is produced, making the

usability of the more saline irrigation water questionable.

When discharging into the wetland it is important that the discharge water comply with the permit

conditions imposed on the Walvis Bay Municipality (Water Act (No. 54 of 1956)) as well as with the

regulations of the Local Authorities Act, 1992 (Act No. 23 of 1992). These conditions are described

under the legal section of this document.

Geo Pollution Technologies (Pty) Ltd

Pierre Botha

B.Sc. (Hons.) Hydrogeology

23 April 2015

14. References

Burbaa G. G; Vermaa S. B; Kima J; 1998; Surface Energy Fluxes of Phragmites Australisina

Prairie Wetland

Everson C. S; Burger C; Olbrich B. W; Gush M. B; 2000 October; Verification of Estimates

of Water Use from Riverine Vegetation on the Sabie River in the Kruger National Park

Langevin C. D; Stewart M. T; Beaudoin C. M; 1998 June; Effects of Sea Water Canals on

Fresh Water Resources: An Example from Big Pine Key, Florida; Vol.36N0.3–Ground

Water – May – June 1998

Lynghus H; 2003 November; Constructed Wetland Area and Pond System at Walvis Bay. 1st

Draft Technical Proposal – Municipality of Walvis Bay, Namibia; Local Agenda 21

Project

Mendelsohn J. M, Jarvis A. M, Roberts C. S, Robertson T; 2002; Atlas of Namibia

Ruppel O. C; Ruppel – Schlichting K; 2013; Environmental Law and Policy in Namibia, 2nd

Ed: Towards Making Africa the Tree of Life. Orumbonde Press, Windhoek.

Urban Dynamics. (2014). Integrated Spatial Development Framework for Walvis Bay. Walvis

Bay: Municipality of Walvis Bay.

Wearne K; Underhill L. G; 2005; Walvis Bay Namibia: A Key Wetland for Waders and other

Coastal Birds in Southern Africa. Bulletin 107:24-30.

Page 24 of 25


APENDIXA: Summer and Winter Bird Counts Jul-14 Feb-15

GREBES 619 544

Little Grebe Tachybaptus ruficollis 23 13

Black-necked Grebe Podiceps nigricollis 596 531

PELICANS 6 28

Great White Pelican Pelecanus onocrotalus 6 28

CORMORANTS & DARTER 0 4

White-breasted Cormorant Phalacrocorax lucidus 4

HERONS & EGRETS 13 8

Grey Heron Ardea cinerea 1

Little Egret Egretta garzetta 1 8

Cattle Egret Bubulcus ibis 11

FLAMINGOS 2658 8446

Greater Flamingo Phoenicopterus ruber 247 93

Lesser Flamingo Phoenicopterus minor 1853 8353

Unidentified Flamingos Phoenicopteridae spp. 558

GEESE & DUCKS 285 409

South African Shelduck Tadorna cana 3

Cape Teal Anas capensis 127 184

Red-billed Teal Anas erythrorhyncha 7 3

Hottentot Teal Anas hottentota 12 70

Cape Shoveler Anas smithii 39 76

Maccoa Duck Oxyura maccoa 44 76

Unidentified ducks Anatidae spp. 53

RAILS, GALLINULES & COOTS 261 182

Common Moorhen Gallinula chloropus 211 66

African Purple Swamphen Porphyrio porphyrio 1 3

Red-knobbed Coot Fulica cristata 49 113

WADERS/SHOREBIRDS 106 141

Black-winged Stilt Himantopus himantopus 16 31

Pied Avocet Recurvirostra avosetta 2 14

Blacksmith Lapwing Vanellus armatus 15 11

Grey Plover Pluvialis squatarola 1

Kittlitz’s Plover Charadrius pecuarius 18 11

Three-banded Plover Charadrius tricollaris 14 3

White-fronted Plover Charadrius marginatus 22 15

Unidentified Charadrius plovers Charadrius spp. 9

Marsh Sandpiper Tringa stagnatilis 2

Common Greenshank Tringa nebularia 2 2

Wood Sandpiper Tringa glareola 2

Common Sandpiper Actitis hypoleucos 1

Ruddy Turnstone Arenaria interpres 1

Curlew Sandpiper Calidris ferruginea 7 1

Ruff Philomachus pugnax 47

GULLS, TERNS & SKIMMER 346 80

Kelp Gull Larus dominicanus 169 20

Grey-headed Gull Larus cirrocephalus 2

Hartlaub’s Gull Larus hartlaubii 175 60

Total 4294 9842

Page 25 of 25


Documents

AN ESTIMATION OF WATER AVAILABILITY FROM THE WALVIS …