Gully-affected areas in the Kunene region: looking for suitable locations for future citizen-science project

Abstract

Land degradation in Namibia is currently threatening livelihoods from several regions of the country. One of the major causes of land degradation in Namibia is soil erosion, which produces very critical ecological, landscape and economic damage when it manifests in the form of gullies. The development of standardized methods to detect and monitor the evolution of gully-affected areas is crucial to plan prevention and remediation strategies. Previous research supported by Integrated Land Management Institute (ILMI) and German Aerospace Center (DLR) was focused on the development of methods to detect gullies automatically from satellite remote sensing data (Vallejo et al, forthcoming). Although the results are valid for carrying out a preliminary large-scale spatial mapping, the satellite images are not usable for a detailed modelling in time and space. For this reason, new methodologies are proposed to address the problem from a different perspective, this time using the local inhabitants as a citizen scientist in a crowdsourcing approach. To set the foundation of this project, planned for 2019, it is necessary to identify several pilot areas where there are gullies of different types and where the local inhabitants are interested in collaborating. Therefore, this working paper intends to document a field work campaign carried out with this aim. +264 61 207 2865 +264 61 207 9865

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Integrated Land Management Institute (ILMI)
Land, Livelihoods and Housing Programme 2015-18
The Integrated Land Management Institute is a centre of the Faculty of Natural Resources and
Spatial Sciences (FNRSS) at the Namibia University of Science and Technology (NUST) committed
to develop reputable and multidisciplinary research and public outreach activities in the field of
land, administration, property, architecture and spatial planning.
The Land, Livelihoods and Housing Programme
2015-18
aims at deepening and expanding the focus
on these three key issues in Namibia. The programme was developed to guide ILMI’s activities by
organising it in four aspects: institutional, environmental, fiscal and spatial processes.
Gully-affected areas in the Kunene region: looking for
suitable locations for future citizen-science project
Enquiries:
Kaleb Negussie
T:
F:
E:
W:
Summary
Land degradation in Namibia is currently threatening livelihoods from several regions of the country. One of the major causes of land degradation
in Namibia is soil erosion, which produces very critical ecological, landscape and economic damage when it manifests in the form of gullies. The
development of standardized methods to detect and monitor the evolution of gully-affected areas is crucial to plan prevention and remediation
strategies. Previous research supported by Integrated Land Management Institute (ILMI) and German Aerospace Center (DLR) was focused on the
development of methods to detect gullies automatically from satellite remote sensing data (Vallejo et al, forthcoming). Although the results are
valid for carrying out a preliminary large-scale spatial mapping, the satellite images are not usable for a detailed modelling in time and space. For
this reason, new methodologies are proposed to address the problem from a different perspective, this time using the local inhabitants as a citizen
scientist in a crowdsourcing approach. To set the foundation of this project, planned for 2019, it is necessary to identify several pilot areas where
there are gullies of different types and where the local inhabitants are interested in collaborating. Therefore, this working paper intends to
document a field work campaign carried out with this aim.
+264 61 207 2865
+264 61 207 9865
knegussie@nust.na
fnrss.nust.na
Miguel Vallejo Orti
T:
F:
E:
W:
+264 61 207 2342
+264 61 207 9342
morti@nust.na
fnrss.nust.na
Document Note: No. 1/2019
Date: January 2019

NEGUSSIE & VALLEJO ORTI
Gully-affected areas in the Kunene region
ILMI Document Note No. 1/2019
Page 1
!
This!document!is!a!report!submitted!by!the!authors!in!fulfilment!of!the!requirements!of!a!small!grant!from!the!
Integrated!Land!Management!Institute!to!undertake!fieldwork!in!Opuwo,!in!August!2018.!!
!
!
Introduction!!
The!idea!behind!this!project!is!to!find!suitable!locations!to!focus!in!subsequent!gully-related!studies.!
Kunene!region!is!one!of!the!most!severely!affected!areas!by!land!degradation!and!gullies!due!to!several!
reason!derived!from! climate!change!and!inappropriate!land!uses!(i.e.!overgrazing).!Different!projects!
(i.e.! SASSCAL!Task! 41! (SASSCAL,!2017),! EU!Stabilizing! Eroded! Areas! by! planting! drought! tolerant!
fodder! shrubs)! are! implemented! here! with! the! intention! of!addressing!the! problem,! trying!to! stop!
gully! advancement,! and! minimize! their! effects.! Different! solutions! in! place! are! applied! on! different!
types!of!gullies,!therefore!this!area!is!of!special! interest!to! researchers.! Since! the! final! goal! is! to! test!
measuring! techniques! for! gullies! at! different! spatio-temporal! scales,! it! is! critical! to! find! gullies! of!
different!typology!in!terms!of!size!and!shape.!!
!
Objectives!
Our! main! objective! was!to! find! and! georeference! three! suitable! gully! affected! areas,! document!
graphically! their! characteristics! as! well! as! create! contacts! with! local! communities! and! authorities!
mandated!with!land!management!issues.!The!main!criteria!to!decide!on!the!selection!of!gullies!were:!
-! Size!and! shape:! the! measuring! technology! must! be! tested! for! gullies! of! different! sizes! (in!terms! of!
width,! depth)! ranging! from! 2-3! meters! to!gullies!as! large!as!200! m! width.! It! was! also! important! to!
identify!gullies!with!different!shapes!(i.e.!U-Shape,!V-Shape,!etc.)!
-!Accessibility:! finding!locations! easily! accessible! by! car! was! also! a! selection! criterion,! as! measuring!
equipment!(i.e.!GPS,!LiDAR,!Photogrammetry!equipment)!must!be!transported!in!subsequent!visits.!
-!!Feasibility! of! joint! work! with! locals:! Since! the! final! goal! is! to! develop! a! collaborative! mapping!
concept,!it!is!fundamental!to!have!the!commitment!of!local!people!to!do!basic!field!measurements!and!
with! the! possibility! to! send! the! collected! data! periodically! to! NUST!(i.e.! ! access! to! internet,! email,!
WhatsApp).!
!
Study!Area!
The! study! area! is! located! in! the! northern! part! of!
Kunene!region!(Namibia),! covering!different!sites!near!
Opuwo.!Figure!1!illustrates!the!different!gully!locations!
and!the!road!connections!from!Opuwo.!
!
Figure!1.!Location!map!of!the!study!sites!visited!in!August!2018.!

NEGUSSIE & VALLEJO ORTI
Gully-affected areas in the Kunene region
ILMI Document Note No. 1/2019
Page 2
Results!!
After!several!visits! to!different!locations,!the!following! gullies!were!selected!and!described!for!future!
studies:!
!
Gully!1!
This!gully!is!classified!as!a!small!gully!(<!5!m!width!and!1!m!depth)!which!has!been!treated!in!the!past!
during!SASSCAL!TASK!41.!It!is!especially!Interesting!to!test!the!capabilities!of!measuring!techniques!to!
monitor!gully! dynamics!in! detail!i.e.!how! is! the! bush! filters! efficiency! and! effectiveness!through! the!
years.!Our!contact!person!in!Erora,!where!Gully!1!is!located,!is!Mr.!Nelson,!who!has!been!collaborating!
with!SASSCAL!TASK!41!in!the!past.!
!
!
Figure!2.!Photos!of!Gully!1!in! Erora.!Left! image!shows!remediation!works!carried!out!between!2013!and!2017!as!part!of!
SASSCAL.!
!
Gully!2!
This!gully!is!classified!as!a!medium!gully!(5!–!15!m!width!and!1!-3!m!depth)!and!has!not!been!treated!
in!the!past.!As!it!can!be!seen!in!the!figure!3,!this!gully!is!very!active!(visible!roofs)!and!it!is!surrounded!
by! woody! vegetation! in! the! ledges,! which! is! a! factor! to! be! considered! while! measuring! the! gully!
morphology!(i.e.!through!Terrestrial!LiDAR!Scan!(TLS)!and!close-range!photogrammetry).!Our!contact!
person!for!this!gully!is!also!Mr.!Nelson,!who!has!been!collaborating!with!SASCAL!in!the!past.!
!
!
!
Figure!3.!Photos!of!Gully!2!in!Erora.!Image!showing!the!gully!
dimensions! (top! left),! gully! V-Shape! (top! right)! and! the!
recent!erosive!activity!(down).!
!

NEGUSSIE & VALLEJO ORTI
Gully-affected areas in the Kunene region
ILMI Document Note No. 1/2019
Page 3
Gully!3!
This!is!typically!classified!as!a!large!gully! (50!–!200!m! width! and! 10! -30!m! depth).! It! was! treated!as!
part! of! an! EU! project! to! stabilize! the! soil! in! the! margins! of! the! gully! though! plantations! of! different!
local!species:!omungambú,*amukarabize,*omukeka*and*otxipembati.!!As!it!can!be!seen!in!figure!4,!some!
parts! of! the!gully! are!very! active,!and! the! erosive! impact! is! catastrophic! in! terms! of! soil! loss.! The!
dehydration!effect!on!the!surrounding!landscape!is!evident!and!very!detrimental/harmful!for!several!
Himba!communities!living!nearby!and!subsisting!from!different!types!of!farming!(i.e.!goats,!cattle,!etc).!
Our! contact! person! is! Mr.!Tjakazapi! Mbunguha,! who! has! been! collaborating! with! EU! projects! in! the!
past.!This!gully!has!a!specially!scientific!interest!due!to!the!geomorphological!processes!associated,!as!
evidenced!by!the!existing!publications!on!it!(Brunotte!and!Sander!2000!;!Brunotte!et!al.!2009).!
!
!
!
Figure!4.! Photos!of!Gully!3,!14!km!south! to!Opuwo.! Left!and!
right! top! images! show! the! advancement! of! gully! branches!
while!the!image!below!presents!a!general!view!the!gully.!

NEGUSSIE & VALLEJO ORTI
Gully-affected areas in the Kunene region
ILMI Document Note No. 1/2019
Page 4
Further!steps!
The! three! gullies! have!been! selected.! Currently! the! authors! are! looking! for! funding! to! implement! a!
crowdsourcing!and! citizen! science! project.! This! concept! would!include! different! kinds! of! technology!
managed!by!NUST!Staff,!NUST!Students!and!local!citizens.!The!proposed!methods!for!this!study!are!to!
acquire! datasets! through! mobile! application! and! involvement! of! citizen! science! crowdsourcing! to!
complement! existing! remotely! sensed! databases.!This! process! will! involve! farmers! and! extension!
officers!to!record!and!update!field!data!(i.e.!gully!perimeter,!size!and!shape)!on!regular!basis!using!low!
cost! technologies! (i.e.! GPS,! Smartphone! camera! and! drones).! Following! the! completion! of! the! data!
collection,! spatiotemporal! data! analysis! and! reporting! will! be! performed.! Finally! gully! information!
sheets! with! statistics! about! their! evolution! will! be! produced! and! disseminated! via! digital! platforms.!!!
The!concept!note!of!the!proposed!approach!is!presented!in!the!following!illustration!(Figure!5):!!
!
Figure!5.!General!concept!of!project!implementation!for!a!citizen!based!VGI!project!in!Namibia!to!measure!and!monitor!gully!
evolution.!

NEGUSSIE & VALLEJO ORTI
Gully-affected areas in the Kunene region
ILMI Document Note No. 1/2019
Page 5
References!
!
Brunotte,! E.,! &! Sander,! H.! (2000).! Loess! accumulation! and! soil! formation! in! Kaokoland! (Northern!
Namibia)! as! indicators! of! Quaternary! climatic! change.! Global* and* Planetary* Change,! 26(1-3),!
67-75.!
Brunotte,!E.,!Maurer,!B.,!Fischer,!P.,!Lomax,!J.,!&!Sander,!H.!(2009).!A!sequence!of!fluvial!and!aeolian!
deposits! (desert! loess)! and! palaeosoils! covering! the! last! 60! ka! in! the! Opuwo! basin!
(Kaokoland/Kunene! Region,! Namibia)! based! on! luminescence! dating.! Quaternary*
International,!196(1-2),!71-85.!
Vallejo!M,!Negussie!K,!Corral!E!(forthcoming).!Comparison!of! Three! Algorithms! for!the!Evaluation!of!
Tandem-X!DEM!Data!for!Gully!Detection!in!Krumhuk!Farm!(Namibia).!
SASSCAL!(2017)!Landscape*Literacy*(Task*041*Fact*Sheet).*Southern!African!Science!Service!Centre!for!
Climate! Change! and! Adaptive! Land! Management,!Namibia! University! of! Science! and!
Technology.! Available:! http://sasscal.org/wp-content/uploads/external-
assets/tasksheets/task_041_na_ag.pdf!!
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