Date : 12 April 2011

EO Information Services in support of

Zambezi River Basin Mapping

Corné van der Sande, NEO BVSteef Peters, Water Insight BV

World Bank HQ, Washington DC

Introduction : NEO BV

- Dutch Earth Observation independent services company established in 1996- Amersfoort: 17 specialists and >10 part time workers- India: >20 specialists- Monitoring infrastructure and environment using EO- Using change detection for management information and updating maps- 80% of work in Netherlands (municipalities, provinces, ministries and EU)

Background : Zambezi River Basin Mapping

Project Context:- Zambezi River basin requires substantial support in

using modern information products to improve watershed planning and management.

- Focus on the countries of Malawi, Zambia, and Zimbabwe where the World Bank already is involved in several water related development activities.

Information requirements:- 1 For the development of market-oriented smallholder

irrigation, small scale water resources will be monitored in time for water availability.

- 2 For Lake Malawi standard EO products from ESA satellites will be delivered in time related to water quality, water temperature and water surface height.

- 3 Already started projects in the Shire Sub basin in Malawi related to risk reduction will be strengthened with information on erosion hazards due to land use changes.

Driver: improve watershed planning and management for (irrigated) farming and fishing

The EO Information Products :What they are, bring and examples

Small Reservoirs Map- Mapping small reservoir well established technique- Provides comprehensive overview of water stored over time- Based on Envisat ASAR dual-pol images- Not hindered by cloud cover- Twice monthly coverage of reservoir areas in area of interest

(>0.5 ha accuracy).- Automated procedure and validated through NEO’s SignalEyesBenefits:- Present distribution of small reservoirs- Planning of small reservoirs- Functionality of small reservoirs over time Limitations:- Ideally, regional area/volume curves would be established- Method well described and can be performed by University of

ZambiaImpact:- Better planning of village-based irrigation- NRT information on water availability / food productionUsers:- Ghana, Burkina Faso, Zimbabwe, Brazil

The EO Information Products :What they are, bring and examples

- Not hindered by cloud cover- High accuracy (0.1 m)- Fast delivery of information- Good correlation with in situ data

Benefits:- Long-term monitoring- NRT Level Lake Malawi- Consistent time series development is

valuable to assess climate impact on lakeLimitations- Dependence on continuation Lake & RiverImpact- Faster assessment of hydrological impacts

on Lake MalawiUsers- Volta basin Authority in Ghana uses it for

inventory and hydrological monitoring

Lake Malawi water level using ESA River & Lake product

The EO Information Products :What they are, bring and examples

Land use and soil erosionContext:

Already started WB projects in the Shire Sub basin in Malawi related to erosion hazards due to land use changes

EO Products:- Land use maps of 2005 and 2010, 10 meter resolution SPOT5

data. (see example Congo River Basin) For validation we use KOMPSAT-2 data of 1 meter resolution

- Land use change map- Erosion hazard map based on Elevation model and land use

2010- For AOI of 10,000km2 to be determinedBenefits:- Fulfill the need of the World Bank and its partners for updated

information on soil erosion and areas of risk.- EO gives information of a large area Limitations- The soil loss method used is not developed for Malawi- Information on erosion potential in a relative scaleImpact: Up to date information on land use, land use change and

erosion potentialUsers: Institute for Environmental Security, Dutch Government

Congo River BasinAOI: 21,000km2Institute for Environmental Security

Land use 2002Land use 2008Land use change

Erosion in Southern Limburg, the Netherlands:Catchment of 42 hectares, slopes 5 - 10%Loess soils, highly erodibleAgricultural land use types: orchard, arable landIncreased erosion risk, due to:• intensification• re-allotment• change of crop types

Soil erosion hazard map

Introduction : Water Insight BV

Water Insight bv- Located in Wageningen (The Netherlands); Spin-off of Free University Amsterdam- Exists 5 years; 8 employees- Specializes in remote sensing of water quality in optically complex waters

(coastal waters, lakes, reservoirs, etc.)Offers:

1) Satellite services: monitoring of water quality & water temperature for:-early detection of (potentially harmful) algae blooms-Monitoring of dredging activities-Environmental impact assessments (e.g. Before or during drilling and dredging)-Information support services to aquaculture, fisheries, recreation, management etc.

2) Services based on dedicated hand held or fixed position spectrometer for close range water quality measures (ideal for reference measurements or local monitoring)Examples: Daily Algae bloom monitoring North SeaEnvironmental impact assessment Caspian Sea Monitoring Mussels banks Monitoring cyanobacteria blooms in lakes

Clients: Dutch Government, European Commission, Oil Companies, Aquaculture companies, Local water management boards

The EO Information Products :What they are

• Chlorophyll-a (Chl-a)• Total Suspended Matter (TSM)• Coloured Dissolved Organic Matter

(CDOM)• Products are resampled to 1 km (RR) or

300 m (FR)• Missions: ENVISAT-MERIS and AATSR;

MODIS• Timeliness: 24 hours after receipt of

images + 2 x per week detailed bulletins • Geometric accuracy : MERIS + AATSR

about 1 km• Thematic accuracies will be illustrated by

standard error products; Chl-a error is usually smaller than 10%;

Lake Malawi water quality and temperature

Example: North Sea Algae bloom Monitoring + validation

100

101

100

101

50 %

50

%

10 0%

10

0%

20 0%

20

0%

40 0%

40

0%

geometr ic mean in -situ Chl a [ mg m-3]

geom

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ean

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ing

Ch

l a [

mg

m-3

]

Input # = 15 Va lid output # = 13 RM A r egression in log- lo g sca le (1) Slope = 1.070 (2) Inter cept = -0.02 6(3) R

sq = 0.948 (4) R MS =0.08 (20% )

Validation of North Sea Chlorophyll-a (based on MERIS) gives at 19 stations an R2 value of 0.948! Currently the reduction of regular stations is considered

• Lake Malawi is 580 km long and 75 km at it’s widest: too big to monitor by in-situ techniques

• The lake seems to gradually move towards a situation with more nutrients, which is probably due to an influx of phosphorous rich sediment during high river run-off episodes.

The EO Information Products :What they bring

Benefits / Advantages• It was concluded by a large customer of Water Insight that the Chl-a and TSM

products are of the same accuracy as the in-situ samples• Satellite mapping allows the gathering of information in areas that are not easy to reach or in areas where some stakeholders wish to conceal

information• The combined optical water parameters give a remarkable good insight in the

ecological status of the lake • Some parameters (such as the concentration of cyanobacteria) is difficult to

measure in the lab; it is often not measured at all: so cases of intoxification remain unnoticed

• Satellite monitoring offers the possibility of high frequency monitoring providing synoptically information (no in-situ technique could ever approach the spatial resolution and coverage of satellite images)

• Where in-situ samples have to be taken to the lab and analyzed in batches (usually taking weeks to months); satellites provide information within 24 hours

• Since all information is digital from the start, communication over internet to decision makers is inherently efficient

Limitations / Constraints Water quality and water temperature measurements from space are obstructed by cloudinessUnknown atmospheric conditions (e.g. Specific dust storms) can cause unwanted artefactsUnknown Specific Optical properties (what type of algae, which pigments etc) can cause some uncertainty in the resultsAdditional info/measurements In-situ spectral measurement are a great help to validate the remote sensing results and to help calibrating the atmospheric correctionLocal knowledge, Photographs and visual evaluations can provide also relevant informationImpact Improved insights in spatial and temporal distribution nutrients and sediments inputs into the lakeImproved insights in the exposure risks of vulnerable sub-ecosystemsManagement info: where and when to apply erosion controlManagement info: do measures work or is the situation worseningPossibly: information on the presence of potentially toxic species

The EO Information Products :What they bring

Date : 12 April 2011

Thank you

Questions & Discussion