Aberystwyth University

The chronology and hydrometeorology of catastrophic on , South West Foulds, Simon Andrew; Macklin, Mark; Brewer, Paul

Published in: Hydrological Processes DOI: 10.1002/hyp.9853 Publication date: 2014 Citation for published version (APA): Foulds, S. A., Macklin, M., & Brewer, P. (2014). The chronology and hydrometeorology of catastrophic floods on Dartmoor, South West England. Hydrological Processes, 28(7), 3067-3087. https://doi.org/10.1002/hyp.9853

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Download date: 06. Oct. 2021 as doi: 10.1002/hyp9853as doi: ci Please Record. of Version the and version this between differences to lead may which process proofreading and pagination typesetting, copyediting, the through beennot has but review peer full undergone and publication for accepted been has article This Accepted Article The chronology The hydro and S.A. Foulds S.A. 1 Institute ofGeography Institute Earth Sciences and *corresponding author: [email protected]

*1 Aberystwyth University meteorology of catastrophic meteorology Dartmoor,on floods of +44 (0) 1970 (0)1970 +44 622580 , M.G., Macklin southwest England southwest Llandinam BuildingLlandinam Aberystwyth Wales, UK Wales, SY23 3DB SY23 This articleis protected by copyright. All rightsreserved

1

and A. BrewerP. and

1

te te this article this .

implications for Accepted Dartmoor on after peninsula southwest variability of quarter last were withDartmoor high associated 1940s declinein general magnitude the mid bycharacterised widespre 1800 ca. AD to research this Articlealternating flood short world catastrophic flood space short ofa time ‘’ hazard experiencedin Europe Extreme f

1946 . warning. instrumental instrumental . However, Local - to

lood of the of - , similar, sedimentary to archives late

type hydrometeorologicalcould events become frequentmore predates gaugedpredates of the beginning records flow meteorological extends the s the 19 19 Given thedanger posed by using lichenometry understanding are -

NAO analysis of longer of analysis rich event th flow(last records 30

and early 20 the widespread most and often , th and flood

can lead and 2): and 2): the incidence of heavy notably declined daily rainfall and receiptof cyclonic andsoutherly typesweather

s century and

are particularlybecause are e dangerous upland ad ad flooding,with particularly large records show records that particularly, upland in - and riskon riversmanagingand flood tha to very little time orvelocities no highflowand for poor periods last over2 the th

flood series flood southwestof centuries . - between wasthat term flood Results showResults period the annual, and annual, seasonal daily totals rainfall This articleis protected by copyright. All rightsreserved Abstract - 40 years)

. ca.1850 . Since of flooding. of extreme extreme

particularly marked after particularly marked 1910 frequency

1): 1):

that do that not ade and historic the most floods,

and

1946 The The peak is often is often mountainous al - England there are 3 centuries.3 ,

, - flood

and frequentand fatal type of fatal type of related related to 1900 which 1820 xtreme limited by quately cover - period rich periodson

there –

has practical has practical (Dartmoor) t

mid concern totals rainfall the the 1930s/mid drain Dartmoor drain

in warminga sub areas

has been In contrast, - of of flooding natural natural 1940s

over the over the events - the decadal decadal . s in the in

use of These that

back back was

in

a in - . .

Pall 2011)2006; et al., rise temperatures eventshydrometeorological could become more frequent types ofthese Rumsby,Macklin and 2007 al., 1992;1997;Macklin Macklin, et Merrett and Macklin, 1999; and (Dobie Wolf, and el. at al., 1998;etet Delrieu al. well causing as warning,for time 2009), al., typically 2 capableof delivering rainfallstorms mm of short period >100 a (Gau time in of conditions Extreme INTRODUCTION Dartmoor Flash floods; Keywords

Accepted totend Article ,

2007; et Marchi 2010) al.,

floods represent floods combinationa of

. These catastrophicevents. These are usually with near associated affect flood riskmanagement; catastrophic s ignificant flood impacts flood 1953 , leading, intensification of to the small - 5 hours. short Due hours. to 5 ; . Carling, 1986; Acreman,1989,Carling, 1991;1986; upland upland

,

2005 economic economic ; Roca Davison,; and 2009 event can be devastating, ; Gaume etal. ; catchments .

Such ,

there are concerns concerns extremetherethat are impacts lichenometry; This articleis protected by copyright. All rightsreserved severe severe

in the UK in the lag times

and todamage infrastructure and , storms are storms are usually origin in convective 2004, 2004, 2009; Barredo Norbiato 2007;

hydrological cycle meteorological and hydrological and meteorological often often North Atlantic Atlantic North Oscillation; , high , flow and limited velocities

). and Ireland

Given the danger posed by leading to losslife of as average global Coxon al., 1989;et

Cargill2004; al., et , typically km <25 (Huntingdon, - stationary (Guttierez , as, me et

2

.

riskwithflood reference global anthropogenic warming bycharacterised flood Longfield and Macklin, 1999) long separate years) records and northern in A oflimited evidence of examining bias (2007) Barredo’s beginsdatabase 1950 in Likewise, flood andebris average which frequencyflow coverage data has of temporal t steepland years) andevents eventsflood in important data European requires However, answering about changing questions frequency flood magnitude and he he flash flood data Accepted Hannafordlthough (2008) Marsh and Article - rich , makes makes , sufficiently long record

– catchments where are floods are flash ungaugedcommon

instrumental data hydrologicalmeteorological and flood , elucidating their short timescale - term trendsshort term from . analysis

data presenteddata by compilations western Britain This isThis important because longer - the poor poor periods relatively

temporal trendsover suc compilation appreciable

of of hydrological the to change. climate to historical temporal short short

(e.g.Gaume et 2009; Marchi etal., , a . .

, their analys

s s well identifying as clusteringduring ofGaume et al Indeed, theIndeed, last 2 I

t is t of of respect,fluvial this a activity. In climatic variability of climatic variabilitythe Little Ice Age of flow records from gauged which showflowoften sites from records

s Marchi et al., (20 Marchi et , which, , therefore,, trends difficult,particularly majority the of as - term variation ( This articleis protected by copyright. All rightsreserved demonstrate and meteorological . are i In UK, similar ha the problems s was based relativelys wason based (34 short h periodsh (Robson short

constrained constrained byuse the . importantto understand day present ,

(2009) (2009) - - term records are to needed records term 3 centuries3 ha 10 d

Rumsby and Macklin,Rumsby1994; and

)

significant upward

covers 14 yearscovers 14 details characteristics

series European al., 2010) ve

been been lthough

, . (last 30 (last alternating

2002). 2002). of of

For example, , whilst,

34 and recent recent flow flow fluvial and and fluvial

are ve years. of of recent -

40 trends trends led to led

severe - 44

a .

(Acreman, 1989) 1989) (Acreman, and itrecent that issignificant of cause common management, especiallywhere (Rumsbysystems and 2007)) Macklin, century floods that Furthermore, placingimportant for short with sub of200order lichenometrythatconfirm can al., Gob et Warburton, 2002) ( Beacons Brecon UK.Subsequentinstudies the theYorkshire Dales Macklin lichenometry deposits inin upland used and involves: catchments theUK (1) identification 2007 Rumsby, al., 1992 et and Pattison Lane, (Macdonald data using documentary/historical Black,2010; and Macdonald, 2012; A lternative

Accepted historical Article

et al. et -

decadal characteristic of 2003, ; and Merrett 1999; Johnson Macklin, and 2002; Warburton, approaches - ; 300 years, as well 300 years, as identifyingassociated underlying controls as climatic ,

relative magnitude flood

upland and (3)evaluat (1992) (1992) this first applied technique in the northern ofPennine uplands ; Gobet al., (although thelatterappear to have more been frequentin many

2008, 2010) scale , M dam steepland 2012 acklin Rumsby and events(17

variability wall to analysis to gauged of data ) and extreme upland floods - term flow records in a a termin temporal morerobust records flow context 2003,

failures and overtopping failures ion Mediterranean

and South America2001) et al., (Maas significantly geomorphological valley floors have impounded valley been floors th

of - 2008,2010 of 19 relative magnitude relative based magnitude on boulder

the NAO th This articleis protected by copyright. All rightsreserved boulderbased dimensions,, on showsoften

centuries) , which,

2007)

extend extend the

catchments )

. . latterapproach beenThe widelyhas , Lake District, (Johnson and and ENSO and

has practical implicahas ; (2) ; summer - sedimentological sedimentological were appreciably larger than were larger than appreciably

involve

(Merrett Ma and flood flood

is inadequate overspill design record extremerecord of

. flash haveflash theUK floods in (Maas and 2002; Macklin,

These find

frequency extending the floodextending the series methods ( tions for risk tions flood for .

of of ings are cklin estimation estimation T have served to have served to he most boulder

Macklin and Macklin and flood dimensions. dimensions.

1999 Macklin s, - 20 ), . berm in the in using th

.

Accepted communitiesthetheir in UK. toclimate episodes of its changeprojections riverfuture impact and on valleys and can be controls which the southwest in of England to be in placed a this way in First,record twobenefits. clear has Dartmoor on primaryThe 2010) Macklin, that communities may particularlybe to(Lewin extremeevents vulnerable flood and Article the lightin of magnitude and frequency of southwest Milan, 2008; 2012 and Johnson 2002 Warburton, northern since the1990s,British uplands significaAlthough a 2008) seriouscaused damage to

. short

England and Wales

England (Table - term aim of this paper is to construct ofthis isto aim paper over the lastover the climat .

evaluated

instrumental data cannot provide. ) . How. e change nt research of amount on hasextremein been focused the floods ever, several recent ever, several , ca.

1 whichis masonry spillways ( )

large floods , and (

150 but but Macklin al., et Merrett 1992; and Macklin, 1999; ; Macklin ; most of most

- increased riskin flood upland/upland fringe there 200

particularly linking in past floo important This articleis protected by copyright. All rightsreserved

years are and Rumsby,2007

this work has in

this region no longer

a record highresolution of activityflood using

summer summer more M it enables recent ason and Hinks, 2008; Walker, Hinks, and 2008; ason Walker, lichenometry meaningful temporal context S - econd, econd, possible term term

. flash flash floods havein occurred directedbeen towards

This isparticularlyThis important data ; Watkins and ; and Watkins Whyte,

. Extending the flood the Extending . to to evaluate the devastating floods climatic climatic d ,

.

m AOD) is 8.1 AOD) m generally Meanand cloudy cool, annual summers. temperature at (453 present ofThe climate temperate,typified ismaritime Dartmoor wetby winters mild, fringe many river channels. Harris, and (Ballantyne 1994) in abundant headwater ca steeply upstream. extreme depositsflood are an (Cenderelli the of rocks 2 (Table berms inwhereshallowand gravel has accumulated sand wide, valley Boulder bottoms. sedimentology, location.geomorphology and Typically, Boulder production in(peak the 13 result, a deposits placer (Beer Scrivand s pluton theCornubianmost of batholith ( extensive area (Figuresouthern upland in Britain 1) issituated Dartmoor on the STUDY AREA Accepted Articleerosion graniteubsequent of surface the ,

on hand theother - ) where rivers interior thegranite leave Dartmoor of and cross the berm fine metamorphic aureole - grained sediment on

d Cluer, the Cluer, at d gorges1998) terminus steep cascades. and of These o deposits were

C and annual precipitation mean is2058 mm Boulder ,

tchments ontchments Dartmoor, sourced from th - tend to be restricted sized material in river channels riversized in material andon hillslopes is channels

orientated theiron b

southwest and 15

differentiated differentiated from and ener . Dartmoor has been historically possibly th Typically, , -

16 1982) 1982) This articleis protected by copyright. All rightsreserved

peninsulaof the UK th Chenal. et

centurieset (Thorndycraft 2004)) al., led the to formation of glacial glacial in wide,low boulder

to to - mine waste mine axis’,very steep deposits deposits ,

1993) and - berms

er and s represent treaming sites treaming . gradient valley floors. As valley gradient floors. , forming well imbricated and dip and well imbricated

(Evans al., 2012) et Mineralisation

based on differences based in

confined gorge sections (Burt Holden and 2010) form relict

extensive ‘streamed’ ‘streamed’ expansion bars ing

the most periglacial

the are locatedare

eastern and softer tin (Sn) tin for tin for .

that -

. .

individual measurements individual construct known were age to used present use s to temporal to coverage better provide were combined species of Pertusaria (Figure 2a) (e.g. growth derivedto the same rates for lichen andlith dating, whichindirect relates the sizelichen growing of on Macklin 1999; Macklin, Rumsby, and 2007 UK technique datingLichenometry standard isa for coarse METHODS thelevelabove of flood deposits to dating the lichenometry (Table of number study contain reaches a gro whichlichen prevents from when using problem on Dartmoor lichen dating presence vegetation of isthe dense and characteristics details size(mean 5. location studyFigure showsof the 1 catchments

Accepteddeposited Article gravestones everal species lichen of on all

Pertusaria aspergilla ,

AND DATA Rhizocarpon geographicum Rhizocarpon 7 boulder within km ) . In study, In the present . four 2 )

2 the last in size

(Figure 2c were fou - ). areThese berms on terraces usually which situated lie berm units berm

on control surfaces of of .

200 Table Table flood record lengthflood by boulder indicated nd nd to have similar wing ) because ) -

. In total, 15 graveyards 250 years were selected to date to date wereflood deposits. Both selected lichen size 2 flood deposits flood on boulder on

shows catchment summary morphological This articleis protected by copyright. All rightsreserved

2b) (Figure a singlea was species )

. (Macklinal., 1992 et . The most commonly The most is method used

- common common early 19 age relationships - Diametralcorrected growth rates, for berms

size which km to 0.2 range 24.3 from that ology surfaces known on of age

, (Figure - Pertusaria age relationships . As result,the. a majority of

th cannotbe dated using species ( -

grained grained flood material century. and 4 4 and surfaces 2 c)

not not .

granite ; Merrett and Merrett and ; corallina

giving a total giving of total 173 a P

orpidia tuberculosa It It was necessary consistently

of unknown age of - berms. A berms.

; these; data structuresof

and

in the 2

.

boulder size relativeboulder approximation of givesthe an quantity magnitude, size of and largest thethree withinon boulders a using deposit flood tape a measure. To 1 that berms ofmeans dates the oldest lichen age/sizeincreasing true (observed)between surface level inadvertent local rates, years age surface within1 to M predict to (Figure 3 photographed known described of or (either during/shortly age after the lichen of batch 2009). test the accuracyreliabilityTo this method, second of a and singlelargestspecimen The with rates consistent species published these for (Armstrong yrmm lag colonization 5 ost predictions ost - Acceptedestimate 2 Article 5 of of

from from - years 1

accuracy, there is a a accuracy,there is for for ) ). R surface age - years 2 the true P m measurement coalesced specimens of , rather than, the relative magnitudeofevents, b flood is orpidiatuberculosa icro egression r measurements

= periods

- are to accurate climatic conditions 0.96 . . The gravestone age , then comparedwhich be could to the . , are 0.2 are ,

A equations coefficient of coefficient of <10

, as reported by workers reported other et al., as 2008) , (Gob small of number predictions statisticallycorrelation (r = significant

per boulderper years was -

0.5 yrmm and 0.7 + age and age and dating (i.e. error

10 years shown in

for deposits.more recent for collected from gravestones collected from and probablyvar to relate , competition,

This articleis protected by copyright. All rightsreserved are indicativeare only correlation between observed predicted and - - berm unit 2.0 yrmm - 1

of of the Figure 2 for for R , nutrient, enrichment hizocarpon geographicum observed . was used - 1 Although show test data good a

-

for for axiswere measurements made were deviate , Pertusaria

and tomayand be accurate error increases then then

age, withage, some accurate

true and Bradwell

for datingfor (Bradwell, iable colonisation iable

in theof order (Table 3) rearranged and

age 0.394

, species, species,

independent

(Table (Table

and , = p

event

and berms

, 2010). , ) with Althoug . This This . , 0. , 0.023 3 16 ) . 7 - used 2 - 1. ca.

3 ) h

3 .

flood recordedhasthatflood been in documentaryneed sources documentary giv data comparing al., 2009). (Rodda et forgotten tennear populated events areas floods (www.dartmoorarchive.org) (www.dundee.ac.uk/geography/cbhe) and British Chronology of Hydrological Events A magnitude flood on Dartmoor approximationsare only. values (Costa, highloadsand can sedimentincrease densityfluid decreasing thus motion threshold areconditions particle bedsfor largerwithmotion for entrainment to related largeeffects can also boulders, cause flood characteristics, within ensconced mayin asupplyincision reduction caused have sedimentbecame river as channels terraced evidence of clear berms predatethat theearly and this of phase 1800s incision incision slope and channel sedimentflood

Accepteddocumentary historywas flood compiled Article ( Table 4 Table related torelated 19 ,

with oftenmost the described the‘worstfloods as living in memory’ documented flood dates documented withflood

and

) 1983). these Allfactors mean of that dimensionsboulder inferred and is closely sediment to linked such as and availability

their Macklin al., 1992). own (cf. et valley fills

th the e little or no or little e Considerable caution shouldConsiderable also be exercised when

and 20 and grain shape, imbrication, grainshape, geomorphological record. - , channel

(Costa, 1983; 1983; 1992; Lenzi(Costa, al., 2006). et Wohl, allowing th

century on Dartmoor deposits flood d recorded to be reliable ( de compar This articleis protected by copyright. All rightsreserved ) coupling. geomorphological record geomorphological information database database the from topographical texts, the from journals, supply isons to be madebetween Dartmoor ArchiveDartmoor , shielding

T and , which be affected, can by Ancaveat important is here is limited is here evidence of tight packing and poor sorting tightpacking poor and - regarding

to

e xtreme events quicklyare - flood variations in sediment variations in flood , armouring,

notnecessarily have

event magnitude, a C s hannel hannel , although there is . Because Because

and protrusion and

k nown bed

that Threshold only .

reco need that data to be Despite excellent ( Centre Data data centuryfrom rainfall Pri presented earlyPrincetown) in some available records from are annual meteorological tables wetmarkedly covers it as valuable the longest inlocated Princetown, ce Holne and Dartmoor,from Ashburton on southeast well as various records as from control ofthe climatic several sources data NAO, have been used. records Rainfall allowTo climatological and Meteorological data the photographed, is true date flood unknown. in1956 or Despiteoccurred 1965. the theresultingthat fact boulder can also Documentarybe mis floods Dartmoorshow1938 ‘greatflood’ in on often Indeed, misleading.are (1939) whphotographs of Worth’s shown byAs floods in recent (Fouldsthe UK al., statements 2012) et this nature of living common and‘great flood’ are memory’ t in geomorphologicallybeen effective

rds. rds. Accepted Article upland examination First, in Reports Transactions and of the AssociationDevonshire www.badc.ac.uk zone short duration (ca.short duration 3 rainfall rainfall rainfall

of considerableinterest (Worth, of 1924). considered

of of the to sedimentary rainfall underlying and archiverelation in series series relatively early data coverage, there are coverage,data there are Dartmoorntral ncetown in the areain ).

when making comparisons withwhen making sedimentary comparisons flood

. - 6 related totals, hours) rainfall to highintensity Phrases such as ‘unpre - dated. detailsa couldTable 4 flood that have were This articleis protected by copyright. All rightsreserved

a

period 1 period . . T (Figure 1) relatively

downloaded the downloaded from British Atmospheric he record from Holne isparticularlyhe record from

extual extual flood 87 , were,

two 6 unspectacular - 1945

important limitations importantlimitations these of selected asselected t

and thevillage lies

cedented’, ‘biggestin Data Holne (and from references at he termedat a

overbank overbank event. - berm berm . . Twentieth hese are the

on Dartmoor. on Dartmoor. was i n a a n

.

for other months other wefor the component haveindex principal used Centre of the National ‘high summer’ NAOthe inde Azores Atlantic, Julyhigh overhave been For the used. Augustwe and which seasonal anomalies, movementstrack lowlevel of the Icelandic pressure and ( Gibraltar in trends on rainfall Underlyinghave controls examined been climatic by analysing seasonal be an exact to match. research of rainfallthis itthat results sedimentary as means and are unlikely records 1918) (Worth, stations of flood 1917 likely gaugesstorms are bypassed have rain to likely producingmost in boulder duration unusually accounting the resulting intense, for flood. Dartmoor, are unusualyet on far mm this appearsfrom to event have been provides an 4) totals do not landslides),(gullies whichand sedimentsupply turn affects in These extreme ingeomorphologically small upland floods effective criticaltoare understanding storms, Accepted 2006 Osborn, Article - (sub the Iceland record these short duration summer and autumn/winter NAO. , -

daily) whichcaused ) example of example kind. As of this noteddaily by (1931) of 50 falls Worth

events ( series1821) begins

series rainfall rainfall )

lead to shear highbed and lead stress . ,

which is most towhich applicable is most These factors should considered when interpretingThese be factors the data

x Folland of et al., (series(2009) begins 1850 in berm deposition Dartmoor on - ,

berms in berms in the uplands. we refer to we to periods of refer heavy as the rainfall daily

. other For seasons, baseddata sea on gridded the magnitude and frequency of This articleis protected by copyright. All rightsreserved events

The winteris NAO The on thebased

. (e.g.

A A 1930flood in on (Table Dartmoor catchments

the October

the and flash Despite theabsence of

Second, promote slopeerosion ,

escaped all recording . Historic

( -

e.g. March period March localised Carling,198 al have

d aily rainfall intense ) , short short

use

and - 68

6 d )

. .

early High of beganberm sedimentation earlier medium (ca. rates in and large catchments effective flood Macklin,2003). and sediment preservationreduced of potential older in narrowunits these valleys (Lewin small in catchments, consistentepisodes with valley highrates of reworking floor and ( time ofthe half Figure 5a) to compared peak largest Figure 4, 5) magnitude between data dimensions boulder Figure Boulder RESULTS 1899) begins Atmospheric Researchfor (www.climatedataguide.ucar.edu W orth, 1918; Table , especially

Accepted Article - show 1): that to

4 dated floods todated appear havefloods the occurred around - - mid 19 mid berm f shows the ofshowshistorical magnitude the based on maximum and floods average ca. .

20

tend to The sedimentary ofsmallThe record . . The thisexception patternto issma in found 1850 and ) th .

‘zero lood histories on Dartmoorlood century th

the the

century) boulder and the largest berm sedimentation berm sedimentation c es

August orrespond

and shows Figure 5 sedimentation berm frequency the of In In these 4). There is little geomorphic islittle 4). evidenceThere of 19 ’ sedimentary the archive. , which, ca. ca. 1910 1917 event,1917 which catchmentsaffected many small small dated dated agrees withagrees

with periods ofhigh (low)

(Figure 4) catchments the catchmentsmost the floods This articleis protected by copyright. All rightsreserved - berms todating berms in the early 20

,

a

in of all sizecatchments occurred and 2): and 2):

number ofdocumentary floods rivers

is also skewed towards is also the periods th t his his period century berm sedimentation berm recent mid ll catchments, where the of of ) (Hurrell, 1995 - to high (low) flood high (low) flood

- ( geomorphologically late 19 ca. ca. th

are are

century flood 1910s/ generally th

century, 1920s,

at at this -

series series (Figure .

first first T more more hese hese

.

berms. For example berms. may floods have Dartmoor on have boulder it bedsand that ispossible of (albeit secondalthough there isa cluster ofberm sedimentation ca. from 1940 ca.to km sized isca. catchments of thenotable features Th riverssome 1900 century therewere also events severe ofDartmoor historical on parts that 1890 destroyed numerous bridgesand toappears have one been of the most written and (photographs accounts) of an exceptional theRiveron flood Tavy in 19 late very a been on theRiver severeTavy flood (Table wasmagnitude generally 20 towardsthe declining km trendinThis isapparent catchments, all butespecially>10 systems in drain that so magnitude and frequency the into early 20 preservation greater potential. common e 2 2

Accepted Articleand particularly from in sizein thecut decline inactivity early geomorphic the in ; Table 4 ; Table th /early 20

(Figure 4c significantly .

)

that appear to havethat appear ofsimilar been th th entrained

century - century. off is and especiallyto ca. dates 1930 (Figure marked - 4f, 5b ,

reduced reduced magnitude) a documentary ona theRiver (Table 1944 Avon 4) flood in Dartmoor Dartmoor 1960 two

1930 - in medium and largemedium catchments in were

5c) boulder

This isconsistent This with documentary evidence other notableother (Nov floods - , consistent, with valley ( wider floors 19

to (Figureto present 4 Although h generally low or decreasing or (Figuregenerally low 70 flood record. break flood The smallpoint in medium and -

sized material as bedsized as material (Figures This articleis protected by copyright. All rightsreserved . igh rates ofberm sedimentationigh rates

Anis caveat important that many rivers 4a

(Table 4) (Table - to - 4d - mid 20 mid th , 5a or greater greater or 2,4 Table Figure, 5

century, ember - lower magnitude 5b .

th At the At the19turn of - ), >10 while catchments in load without producingload without century of t one is , b

). t 1894 1894 and Feb ; Figure; magnitude magnitude to on 1890 here y the Although flood T appears to appears to have ca. mid able 4c

4e,4f - 4f, 5b 4f, 20

2

4e ) and th - continued ruary 1900s, ) in the

he century , - th 4f 5c

1990

most , )

5c .

) , .

of phase earlier ( Dartmoor respectively. dates withagree theearliest These some documented of on floods Riverthe Black Tavy and rivermodern was level da of vegetation.dense clear On theRiver a East Okement, berm However, on berms severalhave been estimates age havemade that remained lic dated to theearlyunits 19 where vegetated/over rather than 1940s, isthe case, this If thedrop that theage possible of toberms related these may been have floods overestimated. and the 1930s (Table1940s 4). Due to typical (Table errors it lichen dating 3) is cent documentary notable in events flood the 1840s, 1870s, 1880s, 1890s early and 20th geomorphologically active of all sizecatchments period highlights tothe from 1820 1930 as most total, In 1917 remobilise boulder on Red 2004 despberms, A this surveyreportedly boulders. moved couldwatercourse not of identify henometry henometry

Accepted Articleury ( 142 Table 4 Table Table Table 4 ite ite the presence large clast of boulder - and a - ven Brook (Horsham, moved2012a) butto bedload also failed high ; Figure; 5e). this this lowperiod of quality data and Figures4 5. isshown on ) and represent ) andrepresent

ca. 1930. - berms have dated Dartmoor been on and aggreg geomorphic geomorphic activity - grown - berm deposits. berm - ted to 1804. Berms terraces an unnamed on tributaryof of a th - (Figure 5d) - in geomorphologicaloff t activityto date may

ven Brook produced lichen ages ven 1785 Brook of 1726, and century

boulder Itis However, were there series a also older older . These These . - berms lieberms on terraces above thelevel of flood . This articleis protected by copyright. All rightsreserved

difficult to reconstructdifficult activity to sites flood at This 110 covers yearThis period a of series terraced

and flood crises flood and s

in features cannot be features dated by

the channel the bed. flood flood deposits associated withdeposits on Dartmoor.on of

documented ca. ca. 3 High August in flows - 4 m m above 4 ating data ating data from

he

ca. any floods in in floods

an the

.

last quarter ofthe quarter last negative NAO Accepted withassociated convective and ‘cloudbursts’ withwhich documentary s corresponds of evidence NAO influence exertsThe strongest over on itsrainfall specific for months of the year. long of may not (Figuresignificant impliesrainfall inand 6b). This that events floods some months patterns,onlyseasonal January, in and November August correlations July, are pushed further and(2009) increased al., cyclonic activity correlated Article changes rainfallsummer and months this totals withassociated cyclonic andsoutherly types ( weather with Gibra the historic relationshipsseasonal with NAO. the on controls frequencyflood magnitude. and from 18 thelightofIn climatological and Meteorological on controls - al term NAO trendsterm NAO rainfall as proxya flood frequency for and will valid only be 2 have a haverelationship a direct with theNAO,suggests whichturn in analysisthat 0 rainfall totals totals rainfall - ( 1930 Figure evidence of evidence of ltar phases phases south than usual /1940s - Iceland index NAO (Figure 19 6a th ,

6c early 20 in 1878, , instrumental data data instrumental , have been to analysed examine climatic and wetnumber of daysand , Figure, high th geomorphic and hydrological 1880, 1880,

.

centur 7a Although daily show extremes rainfall similar ) with the in NAO ‘high summer’ 1890 This articleis protected by copyright. All rightsreserved During ies , s (Figure 8a) 8a) (Figure ,

1917 1917 ummer In terms ofrainfall slow moving 6a the the Dartmoor floods

, (1876 and wetdays 6c winter year (October half and 1930 and 1930 everal large , Figure, rainfall - as as the Atlantic 1945) are are 1945) positively correlated Figure Dartmoor Dartmoor during summer, the cyclonic storms during storms cyclonic totals totals 7b ( activity Table Table 4 8b

are , ,

7c summer summer there are there are distinct ,

wer 8c negatively ) totend and be dex of Follandetdex of ). on Dartmoor Dartmoor on ) storm . e

During the During the During the During the above above floods floods -

track March

is ) .

year, but is year, com but most Leaning 2005; Rainfall Brown, and this typeany2012). of can occur ofthe at time frontal/orographicallyprolonged rainfall (Figure intensified over large (Burt, areas 11) areas ofupland autumnal notable 1894 floods in and1944. inwas flooding January (Tableand November 1929 serious well 1927 as other 4), as increas related onwinter Dartmoor periods tovalues(Figure positive NAO 7b, 7c) and 9e early and 1920s (Figure 1930s 10) Ashburton Holne, and risePrincetown began to ca. after 1900, peaking in NAO. Following the from high decline a autumn winter and notable rainfallassociated events with anomalous behaviourof periodofhigh geomorphic The (Table is on4) Dartmoor (DJF) floods usual and these willrainfall, events certainly related almost been have to slow moving instr in summer 1784,1826, floods 1840, and1844 1848, there although no are increased an incidence of These periods of correspondhigh with rainfall late 1900s/early1890s, average - 9h). 9h). to From 1910 the mid

Accepted Articleumental .

ed types cyclonicweather andsoutherly there (Figure As result 8c). a 8b, ratOverall,the in association association in with

data data

the UK where positive covering

depressions depressions mon duringtheautumnmon (October io of of (JJA),io documentedsummer autumn (SON)winter and - to - high daily (Figure totals rainfall 9d)

mid 1910s, 1920s late1910s, (Figureand mid 1930s 8a these events. these increased increased - 1920s there1920s were series veryof a wet and autumn activity when the jet wasstream tracking due This articleis protected by copyright. All rightsreserved 7 cyclonic from 1820 from autumn/winter

:3:2, respectively. to wetterto autumn (Figureand winter periods annual G iven theinfluence ofthe on SNAO These negative NAO phases (Figure 7a) and negative phases (Figure and NAO 7a) activity in late 1870s, lateactivity 1870s, 1880s/early late in rainfall in in rainfall totals the 1870s/1880s, at - 1930

conditions characteristicofare NAO anomalies result in result anomalies NAO - /1940s November) surface when sea

.

also covers also some There There were also further south than south further , Figure 9c

the late the

). .

daily rainfall showsdaily (Figure 9d rainfall an increase geomorphologicallybegan floods effective and levelshow of good a majoritytheOver the of late 1960s1950s, and onwards. 1980 there berm sedimentation), with decline, was marked especially minor early a the in wit date, this daily date, approachingwereover and common, 100mm quite whereasafter falls floodberm records, informative 20 record atHolne(FigureFigure therainfall does 5), 4, not extend far enough into the ca.1930 after terms ofunderstandingIn sharp the decline in geomorphologically floods effective rainand thaw probabilityincreased of floods. ofthephases coldest Ice (Rumsby Age Little 1996), Macklin, to and due an Dartmoor.occurred on theyIndeed, be have may concerning references winter floods probably (Figure are theseof 5d) reflection a conditions. 2011). ‘atmospheric rivers’ (Laverswarm,air thesubtropics moist sourced al., of from et are southwesttemperatures high (Webb, and winds 1987), with dominant associated th

early Acceptedcentury allowanalysis. to meaningful Article High sedime berm rates of

20 . Although thereare Although . uncertainties in linking to daily totals boulder rainfall th h theexception h of inone notable event themid

/1940s century. a marked change is evident after a changebefore isevident (Figuremarked after 1946 this 12);

agree inand 1960 large catchments ca.

However, Dartmoor Dartmoor ment , especially, the magnitude and and frequency magnitude of the ntation on the early in Dartmoor 20 boulder

(Table 4) This articleis protected by copyright. All rightsreserved

- However,

, 9f, berm flood record,h berm flood to ca.to 1930,decline at during the last quarter of last of the quarter 19 during the , does this not mean they not have )

, as wellas , as en en more frequent during the the Princetownthe - 1970 smaller in systems

Despite relatively few several - 1960s (which1960s coincides istorical data rainfall

whereas intense document record record th

century is more th ary

century

- .

occurred occurred century t on Dartmoor.flooding peak inwith the smaller a the in with peaks evident are ( south Wales precipitat Lake District.and extreme only studyThe of floods Yorkshire Pennines and North with Dales, Rumsby,(Macklincomprehensive and most 2007). are The those records the for Boulder Dartmoorcomparisons floodrecord:UK The DISCUSSION reduction in isthemarked note heavy Princetown at 1946. falls after daily Dartmoor on berm of age (Table 3). to documentary describe sources magnitude flood totals rainfall) shown (extreme are that not by daily values floods Accepted largest he Article .

, which, is different - These differences are differences to are probably These due berm have datedfloodberm deposits in been many ion variability(Gregoryal. area et a

dated dated

century in the record Welsh

may Macklin R and

flood ca. actually

earlier earlier 1850s and

on Dartmoor Dartmoor theon and in A further I n thelightofn rainfall data to ca. (Macklin and Rumsby,(Macklin and 2007) date to themid date

umsby 2007 north 1970s

ca. (Figure aspect similarity of two the records between ern 1860s, .

These periods agree periodsagree These This articleis protected by copyright. All rightsreserved England 13 ) . -

1940s, rather than 1940s, ca. 19 and second the falling the in ); smaller , T

1991) 1991) the first

wo periods of increasedwo of periods ,

(1): Brecon Beacons where largest the

the geomorphicdecline in activity

, is data setsdata thefor Beacons Brecon

differences short in duration and that between that from theBrecon inBeacons upland areas of theUK upland areasof

. (

falls withinthe southwest falls 3 T ; ):

he quite well (2) inability of (2) inability of

potential overestimation

incidence ca. occurred the19 in 1820 dated 30. with upland with upland upland upland flooding

and

ca.

floods Of particular Of of of flooding in 19 ca.

1 is that 1870 0s, 0s,

th ,

.

frequency remaining atfrequency remaining relatively Macklin, and whilst levels1999), (Merrett in high Yorkshire Dales, magnitude sharply ca. flood declined 1900, despite after flood in markedregions show reduction a magnituflood sedimentary England from northern are in records Dartmoor very to that similar both in effective the floods British uplands the may havein 20 peaked the in flooding Dartmoor many ca. record,with Dartmoor withsimilarities the 20 identified series in quarterflood peaks the the last of 19 ca.1911 berm ofsimilarity degree Dartmoor. with variabilityofthe UK, precipitation area data England from northern also show a Although there isevidence strong ofa signalin regional thesouthwest flood ofthephases European evidenceand of rateshigher sedimentation of flooding duringearlier and activitygeomorphic types weather phases and similar ofthe NAO. the southwestin south th 1880

Acceptedcentury Article flood units Wales also Wales upland -

(Figure 1919 ca.1929 and

in the in .

British catchments Data L N ittle Ice Macklin, (Merrett Age and 1999; Gob et al., 20

early 20 orth Pennines. orth . 13 in the District in to ca.1844Lake

declined declined These data regionalThese data patterns point to of flooding bycontrolled

) from the from , on Dartmoor during the20 Dartmoor on

which appears to appears to which have been period a severe in of flooding th

century sharply - 1935,whilst and documentary (2008) Watkins Whyte’s N orth PenninesYorkshire Dales and

. Although the geomorphologicallyfrequency of

The The also also in the earlyin 20 Johnson (2002) and Warburton This articleis protected by copyright. All rightsreserved peak corresponds increased flood activity increased flood frequency

th - 1859, ca.1860 1859, The The magnitudedeclining of

century is th de duringde the20

century with of berm berm of deposition th a marked marked a

century the half first of and , consistent with consistent , patterns also also - 1880, ca.1891 consistentwith UK th also show from from

th century, increase dated boulder dated

century. In In century.the 08 ca. ).

1850 to1850 on

in - 1901, – .

Sheepmount (Pattison Sheepmount Lane, Riverand 2012), Tay2006)). (McEwen, (>1 x 10 withlowland data augmented oflarge/very historical from areas catchments large ofsimilarity they degree theUK, long across differ from geomorphological records from smallWhilst upland catchmentsflood certain show a and melting persistent rainfall. withassociated snaps subsequent melt (Mayes and 2013) Wheeler, is Dartmoor of the some Merrett 1994; Macdonald,and Macklin, McEwen,1999; 20 2012; ( have summer/ of and southwest north ofEngland. important. be equivalent cells and extent, D trend ca.1700s, a ca.1950that al., was 1992). after (Macklin et especially marked North Pennines athe general decline in competenc flood

and are and

Accepted Article in thetiming ifferences upland floodingcan of UK in the be explained certainly been

by NAO variabilitythe in 3 )

autumn autumn and tracks. winter storm km more significant inmore significant

and rate of melt and rate of melt autumn the stormsin

typically most extreme flows 2

) (e.g. Yorkshire Ouse ) (e.g.YorkYorkshire (Macdonald, atat Ouse RiverEden 2012), T here may events are

uncommon historically, typesthese whereas of event 3 - negative winter NAO 4 o C, compared C, compared to 0 also also during rain and and during rain thaw2012 (Macdonald, events . temperature. differences These that mean more likely theareas,more in latter especially when cold northern

be inbe differences seasonality flood

. The January The (1981mean . temperature and British Although there likelihood little may in difference be the position and

This articleis protected by copyright. All rightsreserved England Scotland and (Rumsby Macklin, and uplands - L 2 conditions ocal such asocal snowfactors, o C across the hills of northern England ofEngland thehills northern across , thaw organisation of organisation of summer

related Dartmoor floodsrelated on terminate abruptly with rapid - instrumental series instrumental e e began thelate in 06 between the between the ) , often often , producing , to, a large

water - snowfall and 2010) 2010) ) have

will also

storm on been

.

extreme floods on Dartmoor Dartmoor extreme on floods and theBritish uplands, and confirm the SNAOthat isa Accepted (Linde 1700 wholeSNAO record the back to 1850, wellas thereconstructed series as back to 1965 than with average warmersunnier and drier, conditions in northwest Europe, from behaviour anomalous its theSNAOin of positivewhich typically mode, correlates rainfall in summer decrease heavy (Burt Ferranti, and 2012), upland to related geomorphically in very uplandsthe effective British corresponds floods with a closely larger catchmentthe areaiscontributingrunoff). late 20 The convectivesmall thedistant stormsin uplands only (because of small percentage a large/verylowland records gauged from doadequately not catchments large record York) (e.g. scaleareas effects these as Due flowsto i attenuate. Macklin, rarely,1999) and ever, generatesufficient lowlandif volume distant to affect Article that noted flash floods catchmentssmall in upland theYorkshire Ouse(Merrett of onlyaffect a fraction of largermuch Indeed, drainage systems. convectiveaffected by isolated (Carling, but these 1986), tend storms events to different catchments kmof size.(< Smallupland 25 in generating differences the scale of flood meteorolo and drainage agricultural intensification (Longfieldand Macklin, 1999), also but These differences are to landpartly due at Sheepmount), Eden either are flood whereas longinstrumental/historical 2007), York and flowOuse at (e.g. records, the upland activity catchments from 1980s small to (Rumsby in 2000 Macklin, and records, Geomorphological flood - 2005 (Figure2005 The 14).period 1965 rholm et al.,2008). These patterns with agree of periods less frequent

including Dartmoor, show Dartmoor, including historically levels low of This articleis protected by copyright. All rightsreserved - rich - use impactsassociateduse with lowland - 2005 was consistentlymost the positive in

or same show period. clusteringover the 2 ) tend to) tend be severelymost gical conditions catchments in th

century d

Macdonald (2012) t is t likely that ecline in in ecline

.

AcceptedBoulder change. climatic seasonality different flood records,will and flood differently and respond to future different thesamethat areas drainageof basi in extreme theuplandsfloods (pre whilst systems, the at time by same heavy declining mirrored and rainfall summer Jones 2012a)2002; corres Hulme, et al., have increasedevents the many in of areas over UK recent decades (Osborn and of totals >150 rainfall whereas convective summer >80 of Article summer to compared a thunderstorm. withThe are former associated rainfall totals diffe significant a byseasonality autumn isdominated and winter(Macdonald, events 2012). is There the severeat downstream sites, floods most as theOusesuch atYork, where flood means entire riversaturates (e.g autumnMcEwen, catchments 2000, 2012; 2006). This to tend be associated with regional contrast, the most In lowlandextreme in large/very areas of floods large catchments etal.,(Folland 20 very controlheat, summer ,on important northwest and in Europe flooding -

100 accumulatingmm over 1 that all tributaries sub and - berm records and i bermand records rence longthe this hydrology rainfallin type of duration event of 09). -

200 3 in mm mplications for flood riskmanagement storms and flash floodsare associated with localised - catchments producing experience high flows, - - - 6 Regional hours. 2007). This is an important 2007). is an This suggests it as finding scale, long duration longfrontal rainfall,scale, which duration - 2 days2 entirefalling catchment, and over an This articleis protected by copyright. All rightsreserved ponding with flood n (uplands (uplands n and lowlands) have may - scale autumn/winter scale rainfall - rich episodes inrich episodes large

on Dartmoor

.

extreme floods in extreme thesouthwestfloods uplands. keyThe aim CONCLUSIONS series extendingthe benefits riverfor ofsmallflood upland theUK. systems in especially when2008), consideringsafetyand they dam have (Baker, obvious into ri theUK inform used flood quartercentury and first UK docoverthat not the twowet thelast very theUK: quarterperiods in of the 19 well normal maximum below the flood discharges for maximum flood. River to largecompared other Figure could(although boulders have been entrained movedbed) along and channel the very likely frequency early 20 the from directlyfrom upstream the assessed importance The of u

Accepted Article boulder Dart at Dart 16 th se

, therefore, therefore, , century shows specific discharges of shows specificof the discharges by of of

- data data (1)that: berm record for theberm record River ( Okement for West

of researchwasof this to elucidate magnitude the largest comparing Austins Bridge ( 1979 Austins in the samein event small

However, drainage area Austins bridgeis>200 the at

(the lastdocumented(the event was1917) August tilizing to a

/half have been floods floods gauged flow and boulder and berm records.Figuregauged flow regional regional no no extreme floods haveon this river occurred the since local gauginglocal station,

geomorphological geomorphological

ofthe 20 occurred sk, suchsk, commontheUS are in methodologies events. The only of of Table 4 Table th This articleis protected by copyright. All rightsreserved . lower than magnitude 19

er

century. This is manyin This typical short gauge of records

in thein mid

headwater T his showsextreme paper that largest gauged on Dartmoor flows ) data data , which just, aboveplots thenormal which

Although data Although palaeoflood are not - to understand flood 19 flood flood catchments ( catchments opened in opened th see

century - of of note frequency relationships of relationships frequency Figure 1 th . Recent . flows

is 1968. It occurred century events and 20

for location for - 50 (2); risk

km km 15

peak flood on the 2 can evident 2

shows ) and

plot plot

are are ) ,

be

th .

.

Office) kindlyOffice) data. supplied summer NAO his toonhelping identifytime species Dartmoor. lichen Accepted wouldespecially We to Barbara (British likethank Benfield Society) Lichen her for ACKNOWLEDGEMENTS flood thangauged significantlyare older extend data recordsgeomorphological to flood rainfall mm withof 24 hours. 316 in catastrophicpotential for iswell consequences by illustrated flood on the a flash precipitationprobable and maximum campsites) impounded Article southwest, especially early 20 A events. historicallycurrently at low levels (1990 large of series elsewhere.floods North upland flooding precipitation largeto extent, a controlled, in events frequency and magnitude frequency magnitude and - Pennines ofsimilar magnitude 2010) without2010) boulder th

small century may pose significantcentury risk pose may uplandflood communities the to in ny

. , in 1970 in

.

or whereor Dartmoor the tohas generatepotential very damaging and floods large increase to levels peak recordedincrease themid in Since upland show temporalvariability catchments marked has increased

( ca. 2007 Table 4 Table

rivervalley floors in locations locations in

) and Cumbriain events duringautumn associated 2009 - by sub it wouldappear thatthe magnitude and frequency of berm deposition, in some parts of with recentthe UK, the a in event may to an lead , primarily, d F where havefloodplains ollowing

data - This decadal variability

to historical2012) (Milan, floods in the in area isca. This articleis protected by copyright. All rightsreserved form a focal recreational a activity focal point of form . ofThe notaccountingdangers historical for

research highlights of the importance at least least at ue to decrease to a in ue heavy rainfall extreme , particularly, where largest the floods We wouldlike also to Richard thank We underestimate of flood risk one Professor ChrisProfessor (Met Folland 450 of of

flooding on flooding is on Dartmoor , -

to possibly the NAO been developedbeen mm (Clark mm - late 19 two decadestwo

th and its

, century and

, , 1995). , whichis

as well as a as effect . ,

The The

on (e.g. .

13. BakerVR. 2008. Paleoflood hydrology: Origin,progress, SeriesA Armstrong R,Bradwell 2010.T. Growth ofcrustose lichens:a review. Scottish GeographicalMagazine Acreman,MC. the Instituteof WaterEnvironment. Management Acreman,MC. References Aberystwyth University.Research, Council Funding throughCatchmentfor theCentre for Wales) Dartmoor. (1868Worth Druid, record at rainfall Ashburton (1858 ofgenerations.Spe benefit future century meteorologists manuscript. field. concerning Horsham

Accepted Article

- The comments of commentsof tworeviewerstoThe improve anonymous this helped 1917)

92

and : 3

This research (Higher byThis project was HEFCW Education supported

documentary flood

, - Finally,owewe retrospective to thanks the - 1950) for 1950) numerousaccountshis for severe weather and of on flooding Mr L. FrostMr L. (Holne, 1917 17. 19 1989.Extreme historical UK floodsand maximum flood estimation. Dr. 91.

Susan Andrew The offlood July25

of Dartmoor rainfalltheof who recordsmeticulous kept for

107 events

( University)(Plymouth , : 170 : cifically, Gill, R John Reverend

from from , th This articleis protected by copyright. All rightsreserved - -

1945) 1945) and 178. 1983theon Hermitage Roxburghshire Water, 1866

Sarah Foulds for Sarah Foulds assistance her in for

3 and

to :

404 1928

the Amery family - 412. prospects. . indebted are RH also to We for for

late 19 their

and Coastal and Coastal Geomorphology

th comments comments GeografiskaAnnaler:

ector of Holneector of and early 20

who kept who kept Journalof the th

the 101

. :1 - .

northernfrom England FerrantiBurt T, EJS. 2012. ClimateResearch HoldenBurt T, J.2010. 2004. S. Burt 2005. Cloudburst uponHendraburnick D Devonshire Association R.Burnard 1901. The great floodof February 15 60 R.Burnard 1896. Dart floods. analysis. Bradwell D Beer 148. Barredo Press,Cambridge. BallantyneCK,HarrisC. 1994. urrance EM,urrance Laming DJC (eds) - 61.

Accepted Article KE, Weather

JI. T Scrivener Geograf .2009. Lichenometric dating: a commentary in lightof some recent statistical 2007

60 . 219 , Major flood disastersin Europe:1950 iskaAnnaler 45

RC. : 57 : . - : 227. InternationalJournal of Climatology Changing temper 1982 - 33 70. , 99. , Changingpatterns of heavyr

. Reportsand Transactions of Devonshire the Association : Me

Series A The P . talliferous mineralisation. In UniversityExeter: of eriglaciation ofGreat Britain 91 This articleis protected by copyright. All rightsreserved ature andrainfall gradientsin the u British :

61 - own:Boscastle The Storm of 69. th

1900.

– Ex Reportsand Transactions of the ainfallin upland areas:a case 2005 eter;

32 . The Geologyof : 518 :

117 NaturalHazards . Cambridge. University - - 532.

147.

16

th 42

August plands : 125 : ,

28 study - . . : .

Colorado the Front Range. CostaJE. 1983. Paleohydraulic reconstruction of flash agency.go Floodin Events Cornwall CornwallCouncil. 2011. MeteorologicalApplications Clark1995.C. New estimates of probable maximumprecipitation in South England. West Batholith,southwest England Diachronousand independent histories ofplut ChenClark Y, AH, Farrar E, HAHP,Wasteneys Hodgson MJ, Bronley MV. 1993. 1 Processesin BedrockChannels boundarychannels: examples from twostudies. case In CenderelliDA,Cluer BL. 1998. Depositional processes and sediment supply in resistant of the Instituteof British Geographers g CarlingPA. 1986. TheNoon Hillflash floods: Sc CargillA, MacConnachie AM, 07. 07. American GeophysicalUnion: Washington; 105 eomorphological Accepted Article otland. v.uk/PDF/FLHO1211BVMH Weather a

spectsof a 59 :12 PreliminaryFlood RiskAssessment. Annex 5: Chronology o (http:// -

14. Geological

2 . :307

Perrett JC.2004. Flash onflood Craigie the Perth,Burn, Journalo m , , KJ,Tinkler EE (eds).Wohl Geophysical Monograph Series publications.environment ajor - 312.

f -

11 ormative E Societyof AmericaBulletin

fthe Geological Society - :105 E.pdf). Accessed 18/05/12 This articleis protected by copyright. All rightsreserved

Ju - onismand mineralization the in 118. e ly17 vent in vent an

th -

132. - 1983.Hydrological and floodpeaks fromboulder deposits in Rivers OverRock: Fluvial -

u pland

150

94 l andscape :1183 .

: 986 - - 1004 1191. . . Cornubian Transactions .

fMajor -

.

AtlanticNorth Oscillation: FollandKnight CK, J,Linderholm HW, FeredayD, Ineson S, Hurrell J. 2009. Thes Reviews southernmostindependent Pleistocene ice capin British the Isles. EvansDJA,Harrison S, VielAndersonA, E. 2012. The glaciation ofDartmoor: the Civilof Engineers Dobie Hydrometeorology Cévennes event8 of Du AyralPA,Bouvier CreutinC, JD, Livet M, Anquetin Lang A, M, Neppel L, ObledC, Parent DelrieuDucrocqG, V, Gaume E,Nicol J,Payrastre YatesO, E, Kirstetter PE,Andrieu H, D Crossing190 W. Plymouth.Luke: Crossing. BevenCarlingK, P(eds) June of 1986. In CoxonCoxonP, CE, ThornRH. 1989. Yellow The River (County Leitrim, Ireland) flash flood uring the - Accepted ArticleChateletJ, Saulnier GM, A,Walpersdorf Wobrock W. CH,

45 – W – Wolf N 9September 20 VivaraisMediterranean Hydrometeorological Observatory. : 31 : . 1888. ineteenth -

PO. 53. 1 Floods: Hydrological,Sedimentological a

. 2

6 100 Y

: 522 : AmidDevonia’s Alps: :34 1953 C - entury - . 52. ears onears Dartmoor: 588. . . The p Wiley ast, 02 in02 the GardRegion, France: a

. . Western p offlood August 1952. : Chichester; : 199 resent,and MorningNews: Plymouth. This articleis protected by copyright. All rightsreserved W H anderingsand f uture istorical - 217 . Journalof Climate . N otices onotices the nd Geomorphologicalnd Implications, 2005. Thecatastrophic flash A

dventureson Dartmoor firstcase study for the Proceedingsof the Institute QuaternaryScie

F

Journalof orestand its 22 : 1082 - 1103. ummer nce P . WH urlieus

- flood flood - .

Greeves T Accepted SurfaceEarth Processes and Landforms channelslope F, Gob Bravard J Ardecheand upper Loire (France). archi F, Gob Jacob N, Bravard J France) and sub recentdynamics and F, Gob Petit F, Bravard J Article Hydrology VelascoD, Matreata S,M BorgaG, M, Dumitrescu DaliakopoulosA, I, GarciaIrimescu J, A, Kohnova Marchi S, L, GaumeE, Bain V,BernardarP, Newinger BarbucO, M,Bateman A, Blaskovicova Loschl L, Aude,France, flas GaumeE, Livet M, Desbordes M, Villeneuve J. consultancyreport2012/01/73 consequencesof a large summer storm and flood in west 8 Wales, FouldsBrewer SA, PA vesassessing in the incision of submediterranean rivers from Little the Age Ice in the . QuaternaryScience Reviews

, Stanbrook , 367 Viglione A.2009. A compilation ofdata European on flash floods. edinaPrecisoV, E, Sempere :70 on initiationon ofsediment motionin boulderbed rivers.A lichenometric study. - P,Petit F. 2010. influence The sediment of size, relative sizegrain and - h flood12on and 13 November 1999. 78.

, , Mackl E.2004 - P, - P,Petit F. 2008. Thevalue lichenometry of and historical

Ozera in MG,Betsonin R, Rassner, sedimenttransport of ,pp.53 .

The ClapperBridge

A Geomorphology ,

Gob A. Gob 2003.

22

This articleis protected by copyright. All rightsreserved 32 :2111 - :1535 TorresD, Stancalie SzolgayG, J, Tsanis I, - P.2004. - 2124. - 1547.

Lichenometric – 94 aC

Postbridge

:170 orsican stream(Figarella River

Hydrologicalanalysis theRiverof Journalof Hydrology SME.2012 - 183.

. Quay:

application historto th - . 9 Causesand th

June2012

Brixham

Journalof 286 .

:135 .Fluvio ical – - 154.

.

precipitation. HurrellJW.1995. Decadal t synthesis. Huntingdon2006. EvidenceTG. intensification for ofthe globalwate 10 HorshamR. 2012 Dartmoor. HorshamR. 2012 HemeryE. 19 catchmentsin the UK Hannaford J,Marsh TJ. United the Kingdom with implications for forecasting. Hand Fox NI,Collier WH, CG. 2004. Geomorphology a of catastrophic flash floodin theArfis GutiérrezF, Gutiérez averageddata updatedto 1989. GregoryJM, J 8

Accepted: Article 56 .

Journalof Hydrology Dartmoor Science 78 ones PD,

. 22 HighDartmoor: Land and People b a . . : 265 : Recordof summer thunderstorms and f

Understanding theDartmoor landscapepart5: summer floodson

106 .

M, 269 InternationalJournal of Climatology WigleyTML.1991. Pre 2008 - Sancho1998.C. Geomorphological and sedimentological analysis 283. : : 30 676 rendsin North the - .

32 High - 679

. 319

InternationalJournal of Climatology - . flowand flood trendsa in network of undisturbed

:83 Astudy of twentieth

drainage - 95. This articleis protected by copyright. All rightsreserved

Atlantic Oscillation: regionalt cipitationBritain: in an analysis area of

basin (CentralPyrenees, Spain). . Robert MeteorologicalApplications - centuryextreme rainfallevents in

Hale 28 loods onDartmoor : 1325 : :London. r cycle: r reviewand -

1338. 11 : : 331

emperatu - 345. . . Dartmoor

11

: 15 : resand - 31.

.

managingclimate change. Lewin J, Journalof QuaternarySc Lewin streams? LenziMA, Mao Comiti F.L, 2006. does When bedload transportbegin in bouldersteep QuarterlyJournal of the RoyalMeteorological Society distributionof orographic rain on the occasion of the extreme Cockermouth Cumbria. in flood LeaningHW, Browning KA.2012. Quantification of importance the ofwind drift to the surface Britain areconnected to atmospheric rivers. LaversDA,Allan RP, Villarini EF, Wood BaryshawG, DJ, AJ. 2011.Wade floodsinWinter products Jones PD,Harpham C, BriffaKR.2012b. Journalof Climatology seasonaland annual extreme rainfall in UK the between 1961and 2009. Jones MR,Fowler KilsbyHJ, CG, 945 Raise Beck, centralLake District, England. Johnson RM, 2002. Warburton J. Flooding and geomorphicimpacts in a mountain torrent: -

Accepted Article 969.

J, J, . .

Macklin MG.2010. Floodplain catastrophesin theUK Holocene: messages for Macklin HydrologicalProcesses InternationalJournal of C

MG. 2003 . . DOI: ience Journalof Hydrology . 10.1002/joc.3503 Preservation potentialLate for Quaternaryriver alluvium

18

: 107 : 20 B lenkinsop S.2012a. limatology :3517 - 120. This articleis protected by copyright. All rightsreserved Lamb weathertypes derived from reanalysis - Earth SurfaceProcesses and Landforms 3533.

GeophysicalResearch Letters

. DOI:10.1002/joc.3498.

24:2900

.DOI:10.1.1002/q

Anassessment of chan - 2911.

j.2024. International

38 ,L23803: 1

gesin

. 27 - : bed - 8.

.

AmericaBulletin valleydevelopment floor and transformationin theBritish uplands. AcceptedMacklinMG,Rumsby HeapBT, T. 1992. Transactionsof the Institute of Br MacklinMG,Rumsby 2007.BT. of BritainGreat MacklinMG.1997. Fluvia SurfaceProcesses and Landforms supplywithin Mediterranean a mountain catchment,southwestern Crete, Greece Maas ArticleJC(e SedimentSystems: Archives ofEnvironmental Change floodingin Andean mountain riversystem: the Rio Aliz Maas GS, and sediment fluxes in the Yorkshire basin. Ouse Longfield SA,Macklin MG.1999. Vol.6 (eds.). Archaeology,Climatology and Oscillation (SNAO) Linderholm ds

:Potsdam; GS, GS, Proceedin .). Balkema: .). Rotterdam; Macklin Macklin

HW ,Gregory KJ Chapman(ed). Hall: London;203 ,Folland

104 6 gs of theDENDROSYMPOSIUM Scientific 2007.

MG.2002. M - variabilitylast the over five centuries

13. : 631 : G, WarburtonG,

CK, lgeomorphology of north - 643.

HurrellJW. 2008.

Theimpact of recentclimate changeon floodingand sediment Ecolog,

297 Changingclimate and extreme floods inthe uplands. British itish Geographers The influence The of recentenvironmental change on flooding

J, 27 -

323 Woodward : : 1087

ElfertsD, Brumelis GärtneG, . This articleis protected by copyright. All rightsreserved Flood alluviation andentrenchment:Holocene - 1105.

Reconstructings

JC, HydrologicalProcesses - eastEngland. In 32 Meldrum os, southernos, Bolivia. In : 168 : , Maddy , .

In

- TRACE 186. ,E - 238. D, MacklinD, ummerNo

A . 2001. . GeologicalSocietyof

- Tech r H, r HelleSchleser G, G

FluvialGeomorphology TreeRings in

nicalReport

300 13

rthAtlantic M : 1051 : G - RiverBasin yearhistory of , , Woodward . . Earth - 1066. 08/05,

.

upland Milan2012. D. Quine TM(ed Dales,northern England. MerrettS Scotland 1200from to present. McEwen2006.LJ. Flood seasonality and generatingconditions in the Taycatchment, Introduction. 68:Weather 3 Mayes J, D. Wheeler 2013. Regional weather and climatesof the British Isles andDams Reservoirs 18: 5 MasonHinks PJ, JL, 2008. Security of stepped masonry spillways: lessons Ulleyfrom dam. 118 floodsin Europeand implications for flo MarchiBorga M,L, Preciso E,Gaume 2010.E. Characterisation ofselected extreme flash Manning forthe River Ous MacdonaldAR.Black N, Reassessment2010. of flood frequencyusing historicalinformation archive and instrumentalsources since AD 1600. Macdonald2012. N. -

Accepted Article133. stream: Thinhope -

P SaundersR. 1951. TheRiver Dart. WestawayLondon. Books: ,Macklin MG.1999. s) Geomorphicimpact and systemrecovery followin .

Wiley: Chichester;Wiley: e,York, UK. Trendsin floodseasonality of River the Ouse (northernEngland) from

Burn,northern England, UK In - - 8. 8.

FluvialProcesses and EnvironmentalChange

HydrologicalSciences Journal

Historicriver response toextreme floodingthe in Yor Area

345

38 odrisk management. Hydrological Processes394: :47 - 360. This articleis protected by copyright. All rightsreserved - 64.

Climatic Change . Geomorphology

7 :1152 g an extremean g floodin an

110 - 1162. : 901 :

138

, Brown , AG,

: 319 : - 923. -

Part1: -

328. kshire

.

71 extreme rainfallsin British the Isles 1866from to 1968basedon Rodda,HJE, Little MA, Wood RG,MacDougall, McSharryPE. application Boscastle to the event. RocaM, Davison M.2009. Royal RobsonAT. 1981. changesin flood frequency,River Eden,UK. Pattison LaneI,SN. 2000. Anthropogenic greenhouse gas contribution to floodrisk in England and autumn in Wales PallAinaP, Stone T, DA,Scott PA,Nozawa PhilosophicalTransactionsof the Royal Society of London: Series A Osborn Hulme TJ, 353 Osborn 2006. TJ. Recent variations in thewinter AtlanticNorth Oscillation. Hydrology precipitation in the eastern ItalianAlps andthe August 29, 2003 flash flood. Nor - 75. biatoD, Borga M, Sangati M, -

Accepted Article355.

Nature society ofsocietyLondon A

345

2002

470 :149 :382 .Evidence for trendsin UK flooding.

M. -

1 2012. Therelationship between Lambweather typesand long

66. 2002 - 386.

360 . Evidence . for trendsin heavyeventsrainfall over UK. the Two dimensionalmodel analysis of flash

: : 1327 Zanon F.2007. Regional frequencyanalysis extremeof Journalof Flood Risk Management - 1343. This articleis protected by copyright. All rightsreserved

T, Hilberts T, AGJ, Lohmann D, InternationalJournal of Climatology PhilosophicalTransactions of the

2009. A2009. digitalarchive of BritishRainfall -

flood processes: 360

3 : : 63 : 1313 AllenMR. 2011. Weather - Journalof 71. - . 1325. Weather

32 - term :1971

61

:

64 - : .

GeologicalSocietyof America Bulletin WohlE. 1992. Bedrock benches and boulderbars: floodsin Burdekin the Gorgeof Australia. Me Webb JDC.1987. 1600: WatkinsS, 2008.I. Whyte Extreme floodevents in upland catchmentsin Cumbria since Reservoirs WalkerJP. onmining Dartmoor,southwest England ThorndycraftVR, Pirrie A StanbrookE. 1994. Publication Palaeohydrologyof Age’)in northern, RumsbyMacklinBT, MG.1996. 499 change: The Tynebasin, northern Engla RumsbyMacklinBT, MG.1994. bandonment teorology -

Accepted Article 515. the evidence the of historical records

: London : 18 2008. Thediscontinuance ofBoltby reservoir,North Yorkshire,UK.

12 :17 . Halsgrove: . Wellington. : 263 : - western andcentralEurope. Britain’shighest daily rainfalls: thecounty and monthly records. 21. , DartmoorForest F 115 - Bra 266.

D, BrownD, 2004. AG. nsonBrown J, AG, GregoryKJ : 217

– 233. River Channeland floodplain response to recentabrupt climate

response to thelast Neoglacial cycle ‘Little (the Ice arms:

104

. . nd. North W This articleis protected by copyright. All rightsreserved Geoarchaeology : 770 : EarthSurface Processesand Landforms Alluvialrecords of medievaland prehistoric tin A

S In - ocial 778.

est Geography GlobalContinental Changes: The Context

History Enclosurefrom to (e ds)

19 . :219 Geological SocietySpecial

8 : 33 : - 236. - 41.

Damsand Journalof

19 : .

Hansford Worth Worth RH.1971. Reportsand Transactions of the Devonshire Association Worth RH.1945. Si Reportsand Transactions of the Dev Worth RH.1939. Fifty Reportsand Transactions of the Devonshire Association Worth RH.19 Reportsand Transactions of the Devonshire Association Worth RH.19 Reports Worth RH.1924. Forty 50 Thethunderstorm of August 14 Worth RH.1918. Thirty

Accepted Article 234 : - 242. and Transactionsof the Devonshire Association

31 30 . David . Charle & . Forty. Forty. Worth'sDartmoor: compiled from published the w x ty - - seventh report (3 - - - - third report(3 eight eight secondreport (3 sixth report (3

repor report(3

th s:Newton Abbott. . Reportsand Transactions of Devonshire the Association t(3 onshireAssociation rd rd rd rd

series)of committee the on the climateof Devon.

series)of committee the on theclimate of Devon. series)of committee the on theclimate of Devon. series)of the committee on the climate of Devon: rd rd This articleis protected by copyright. All rightsreserved

series)of the committee on the climateof Devon. series) of committee the on the climateof Devon.

63 62 56 77 71 : : :153 :69 :91 105 135 - - 86. 108. - - - 121. 152. 169.

orksof the lateR.

.

Figure 1. Dartmoor, Dartmoor, Figure 1. Accepted Article control other dating surfaces in theuplands. ofthe smallercatchments Some are showing study labelled 1 labelled catchments and thelocation catchments of graveyardsand This articleis protected by copyright. All rightsreserved

- 6.

.

Figure 2. Accepted Article withidentified assistance the regional of a expert the from British Lichen Society. Age - size of relationships

lichen species thisused in study. were Lichens This articleis protected by copyright. All rightsreserved

.

a shortly after the eventshortly 1971 (shownwas compilation) after in to 1928 dated using Worth’s, Figure 3. Proximal section of a section of Proximal a Figure boulder 3. and - and corresponds veryand documentedwas in a that wellwith 1917 flood at described this precise l precise this ven Brook, ven northern Based Brook, Dartmoor. on the largest Accepted Article (Sniper’swas Gully)Brook generated that same by the and photographed flood R hizocarpon geographicum ocation by Worth (1918). by (1918). ocation second A berm tributaryon a Red Worth of Pertusaria species Pertusaria

(22 mm) specimens mm) berm (22 this dates 1907 to This articleis protected by copyright. All rightsreserved - berm in a deposited bedrock R of section

.

P orpidia orpidia tuberculosa

(74 mm) - a - 1914 1914 - ven ed - .

age, error bars showerror bars standardage, deviation. one Beca measurement ofmeasurement three was boulders possible. not Fi ( and (3mean and largestclasts) > gure 1.5 <10 km <10 1.5 Accepted Article size, accuracydating berms older than lichen increasing the with range of our used ofimbrication somebecause used the degree at sitesthat meant accurate validated data (ca. data 120validated years3)) show (Table twodeviations. standard 4 . Boulder . 2 ; 4c,; 4d) - berm and largeand flood b

magnitude smallmagnitude plots for - axis Both data. of measures magnitude been have

( > 10 km 10 This articleis protected by copyright. All rightsreserved

2 ; 4e,4f)

use there trendofdecreasinguse isa For thanberms less years 120 in catchments based on

(<1.5 km(<1.5 2 ; 4a, 4b),

maximum maximum

medium medium

.

Figure (b) considered in considered Accepted Article of theand number documented floods associated withassociated the1956/1965 flood. medium 5 . Summary . decadal ,

and

conjunction with error (c) largeFigure catchments. frequency of boulder frequency of This articleis protected by copyright. All rightsreserved bars and bars error .

The The timingdecadal peaks of Hatching 5e represents on uncertainty s

5 - d berm sedimentationberm

and 5e show estimates shown estimates Table in

aggregated aggregated data

for for must (a)

be small 3 .

,

.

Figure 6. Correlation of rainfall data HolneCorrelation data ofvicarageFigure rainfall at 6. (1876 1945), southeast Dartmoor (seeDartmoor southeast Figure with1945), 1 for index (a) NAO location) valuesfor v mm). Statistical significance isshownStatistical significance mm). <0.05. where p total (b) total monthly rainfall, daily rainfall wet (c) and maximum days number of ( Accepted Article in 1917 gauge when therain icarage ended was moved village ( 9 m loweraltitude in m 9 This articleis protected by copyright. All rightsreserved

)

and ran until 1945.

The The original atH record ca. 0.5 km ca. 0.5 - 1917) and Holne1917)

away Holne to

> (1917 0.25 0.25 olne - .

Accepted Article strongestThe HolneFigure rainfall:seasonal (monthly 7. relationships NAO totals) as shown in Figure shown in 6. as This articleis protected by copyright. All rightsreserved

.

213.1 213.1 (Jul mm Types (LWTs).CoefficientsTypes of correlation are shown thetopright in corner (p

- Mar). LWTs are Mar). LWTsare based on

.

Accepted Article rainfall Seasonal Figure and totals 9. daily atHolnemaximum (1876 rainfall The dashed line thechange ofgaugeThe indicates location. This articleis protected by copyright. All rightsreserved

- 1945).

.

Accepted Article Figure 10 . Annual. p shorter Holne record shorter recipitation at Holne,recipitation at Princetown.Ashburton and is plotted is plotted on a This articleis protected by copyright. All rightsreserved

different x - axis scale.

Notethe that

.

Accepted Article Rainfall NAO totalsFigure data 11. and based(2004) on Handet al., with data

from Boscastle 2004, C Boscastle 2004, from This articleis protected by copyright. All rightsreserved umbria 2009 an

d west 2012. Wales

and updated and

.

Accepted Article Maximum atFigure daily totals various gauges 12. rain have that rainfall at operated Princetown, central Dartmoor, sincecentralPrincetown, thelate Dartmoor, 19 This articleis protected by copyright. All rightsreserved

th

century.

.

Accepted Article Figure 1 3 . Summer (July - August) NAO data tofrom 1850 2011 on theindexbased data NAO August) of of Folland etal., (2009). This articleis protected by copyright. All rightsreserved

.

England England and This wasfigure Wales. 174) and updated174) has been in paper includethis to southwest data from England (the dashed line low indicates (the quality/no data associated onwith Dartmoor data

Accepted Article Figure 14 . Decadal Decadal . flood ofall datedfrequency boulder plots lichen vegetated berms). vegetated first published first This articleis protected by copyright. All rightsreserved

in Rumsby and Macklin

- berms in berms

(2007, (2007, p.

.

for theOkement River for at West Accepted Article Figure 15 . Dec . adal adal flood boulder frequency of c atchment area isca.atchment 1

Vellake gauging station This articleis protected by copyright. All rightsreserved - berms berms 3

km , Dartmoor;northern upstream and a 2 .

nnual nnual maxima

flow data data flow .

Accepted Article Figure 16. Specific discharge and notableother and extremesthesouth in

of of annual riversmaximum drain flows Dartmoor that for This articleis protected by copyright. All rightsreserved west England. of

.

Cornwall Boscastle, Cornwall Boscastle, Cornwall Camelford, Devon Lynmouth, Location Accepted Article Table

1

. Notable . 20 Date 2004 August 16 1958 3 1957 8 1952 August 15 rd th

th th June June th

century flash floods in

200 mm No data 203 mm 229 mm total) hr(24 Rainfall

Index values. Index

This articleis protected by copyright. All rightsreserved No data in hrs 2.5 138ca. mm in hrs 5.5 ca. rainfall duration Short inhours 4 181ca. mm

135mm Devon Cornwall and monthly and NAO

1 fatality destroyed. B Camel the floodingon Severe 34 fatalities. destroyed. bridges housesand Numerous damage Flood destroyed. buildings b flooded; properties Over70 ridges ridges

River . .

and

.

- - - NAO - 0.98 0.64 0.64 0.28

Council Cornwall (2005) Burt (1953) Wolf Dobie and Reference (2009) Davison Rocaand (2005); Burt (2011)

.

Table 2. Summaryand Table boulder morphometric ing group ment Catch

2 2 †

Medium (>1.5 - <10 km ) Small (< 1.5 km ) *Denotes thepresence Dartmoor. of undated togrowth. due berms, vegetation Denotes Accepted Article

Lady Brook trib. Tavy River Brook Manga stream Pit Cocks trib. E. Webburn Valley Deep Gully Sniper’s e Watercours Water Fishcombe Brook Red Lyd River Brook Doetor Swincombe Deep Brook Middle Lake Braddon

-

a

uncertainty with photographed in deposited a berm associated 1956 or

-

ven ven

Lyd ombe Swinc Avon Dart East Taw Tavy Teign North ent Okem West Dart Lyd ent Okem West ment Catch Dart West ent Okem West Lyd

1.7 4.5 4.9 2.2 0.8 1.3 1.3 1.4 0.7 1.1 0.2 0.7 0.7 1.0 ) (km a Are

2 0.080 0.098 0.093 0.067 0.164 0.179 0.142 0.220 0.161 0.162 0.153 (m m slope channel Reach 0.155 0.093 0.050 This articleis protected by copyright. All rightsreserved - 1

1965. )

10 15 10 15 10 15 10 (m) h widt floor ey Vall 40 30 50 40 50 30 12 10 25 15 25 15 12 10 25 15 12 10 15 10 12

------

-

berm data data on from study catchments berm 1* 1* 2* 4* ms ber No. 3* 5* 3* 3* 1* 1* 1 7* 3* 1

ca. ca. 1890s ca. 1980s - 1910s ca. 1920s - 1840s ca. length d Recor - 1840s ca. 1950s - 1850s ca. 1950s - 1820s ca. 1950s - 1860s ca. 1900s ca. 1860s ca. 1920s ca. 1960s - 1820s ca. 1950s - 1780s ca. 1920s ca. 1950s

ca. ca. 1890s ca. 1910s ca. 1880s ca. flood dated Largest 1880s ca 1850s ca. 1860s ca. 1880s ca. 1900s ca. 1860s ca. 1920s ca. 1940s ca. 1920s ca. 1920s ca. 1950s

0.33 (0.76) 0.77 (0.82) 0.90 (1.13) 1.20 (m) flood largest of n) max.(mea b (1.01) 1.15 (1.05) 1.20 (1.78) 2.00 (0.96) 1.40 (0.74) 0.91 (1.12) 1.35 (0.59) 0.61 (0.70) 0.90 0.82 (n/a) (0.72) 0.95 (0.31) - axis

.

AcceptedLarge (>10 km2) Article Okement West Okement East Mardle Brook Cherry O’Brook Brook Red Plym East Dart Brook Blackaton Brook Black Erme North Teign Taw Tavy

-

a

-

ven

North North ent Okem East North North Taw Tavy ent Okem West ent Okem East Dart Dart West Dart West Avon Plym Dart East Teign Erme Teign

19.9 21.1 13.0 24.3 13.7 10.3 2.3 2.0 4.8 1.7 8.7 9.0 3.3 3.5

0.115 0.107 0.050 0.046 0.035 0.047 0.072 0.111 0.113 0.065 0.131 0.056 0.060 0.027 This articleis protected by copyright. All rightsreserved

15 10 50 40 20 10 30 20 40 30 40 30 40 30 100 50 100 50 100 50 200 50 100 50 100 50 15 10 ------

3* 1 3* 1 6* 11* 7* 7* 7* 3* 27* 19* 10* 1

- 1910s ca. s /1960 1950s ca. 1920s - 1830s ca. 1980s ca. 1960s - 1860s ca. 1910s - 1810s ca. 1920s - 1720s ca. 1920s 1920s - 1860s ca. 1900s 1800 ca. 1910s - 1810s ca. 1980s - 1850s ca. 1910s - 1810s ca. 1940s - 1800s ca. 1940s ca. 1960s

-

1910s ca. 65† 1956/19 1903s ca. 1980s ca. 1880s ca. 1880s ca. 1840s ca. 1860s ca. 1810s ca. 1810s ca. 1890s ca. 1840s ca. 1850s ca. 1947 ca.

(0.85) 0.91 (0.93) 1.05 (0.94) 1.08 (0.34) 0.35 (1.00) 1.06 (1.20) 1.60 (1.16) 1.55 (0.86) 0.92 (1.32) 1.51 1.50 (n/a) (1.49) 1.87 (1.08) 1.55 (1.06) 1.15 (0.75) 0.60

.

years( aroundDartmoor calculated from regressionequations shown Figure in 2. Mean andone tombstonesand the majoritydata of for these species wereused constructo standarddeviation errors truefromsurface are 3 andyears 10 ( are availableare for Accepted Article Table 3. (late 18 (late R.geographicum Ditsworthy House Warren

True gravestone Surfaceage predictionsof granite gravestones,bridges and other monuments 1917boulder 1917boulder 1917boulder th /early/mid age(years) R.geographicum 105 106 121 100 80 94 87 74 67 63 71 27 24 23 65 27 12 56 54 94 17 95 80 11 58 79 50 81 62 94

); 5); and 12 years ( - 19 - - - berm berm berm Pert /berm

th Rhizocarpon geographicum

century) Porpidia tuberculosa(n = 2 usaria corallina/aspergilla = (n

and size

Predicted gravestone This articleis protected by copyright. All rightsreserved Pertusaria - age age graphs. P. corallina/aspergilla age(years) 1801 1928 1914 1907

114 126 116 137 107 104 species asthey are lessabundant on 16 70 59 70 48 72 68 84 87 97 88 79 61 66 73 16 32 22 79 25 11 77 77 9 - 1839

(n (n = 2

)

5 /berm 7 )

)

). Relatively ). testdatesfew P.tuberculosa

trueage (years) Deviation from - - - - n/a 19 11 21 10 16 14 21 23 10 ------10 10 10 11 1 6 7 7 3 1 5 3 2 8 1 2 9 2 9 3 6 1 2 1 tthe original

); 6 and); 7

.

*Clapper bridges relatively*Clapper are splitmade granite of laid structures slabs small Accepted Article Table 1840 August 1830 1826 August 1823 January July date ary flood Document 1866 January 1854 1848 August 1844 June 1841 October

4 1784

. Docum.

horizontally over 1 Ashburton Burn, Taw Dart Tavy East Dart Meavy and Mew Plym, Dart West location g catchment/ River/ Walkham Tavy, Taw Dart eneral eneral entary historymajor entary on of eventsflood Dartmoor

could not carry the stream the notcould carry long The hour. an about lasted Rain 1841. October 16 the since has which R on the don damage understand the We deaths groom with cart the washed and party wedding the against A it had. was that view majority The 1830. of the record exceeded levelhad current the whether questioned the residents older of some flood 1880 severe the During bridges clapper Postbridge and Teignhead Severe thunderstorm. height. immense reached Rivers destroyed. Bridges Two Bridge at impacts and description Flood to be added a destructive a destructive added to be has week the of mischances weather the numerous To 1841 See October rapidity. with unusual Dartmoor from down A floodcame summer. the during ever known (Dart) River flooded. was and t

wall of water rose up water rose wallof - e was very considerable verywas considerable e 2 central piers made of central boulders. 2 he lower part of the town the town of part lower he

This articleis protected by copyright. All rightsreserved

. and bride away to their their to and away bride *

iver Taw (in 1854), 1854), (in iver Taw - destroyed. dry water courses water courses dry

not been so high high so been not th rose higher than than higher rose

and 17 and

.

th

N/A N/A 3.39 - N/A O NA 2.06 NA N/A N/A 2.13 - N/A

CBHE (1978) (1994); Hemery Stanbrook (1901) Crossing (2012b) Horsham Source(s) Gazette Gazette (1866) Plymouth & CBHE CBHE CBHE CBHE (1951) Saunders Manning

1784

-

- 1992

.

.

Accepted Article 1894 November 1890 July 1880 July 1878 Summer 1873 ptember August/ 1927 1917 August 1900 February January January

Se

Dart, Okement Dart, Dart Taw Walkham, Cowsic, Tavy, Dart, Tavy Brook Cherry Meavy Cowsic, Dartmoor Lyd Taw Fishcombe, Okement, West Sniper’s Gully, Brook, Red

-

/ west / a

-

ven ven

17 of flood hitherto record thethan was flood2 This to a (Okement) 15 on thaw rapid extraordinarily on 13 storm snow heavy andA mild. Wet flooded. works gas night all 1894.Rain November 14 of that by eclipsed was 1890 July of great flood The Dartmoor. runningoff streams the other and Tavy River the onfloods 16 Devon and began in storm The bridges. several away and carried 1880 than higher Tavy rose River The Storm”. Great “The drowned. miners Three before. known ever was than RiverThe Tavy thunderstorm. Tremendous fury. with unabated the time continued storm rapidly rose Brook Cherry lighting. and Thunder fat One away. washed bridges Clapper life human and property of loss bridges down broken and cattle, away sheep washed railways, up tornhas which inundation, Daily fall of 81 mm at Holne. mm 81 of Daily fall affected. badly particularly was Lydford area around The Dartmoor. on flooding widespread and Heavy rain torrents. turned to and streams Rivers description. ordinary th exceeded which rain heavy Extremely and flood. Thunderstorm th th .

, and produced great great produced and , , flooding the river river the flooding th –

This articleis protected by copyright. All rightsreserved

July 1890 July

two flood peaks. peaks. two flood and caused great great caused and

Cornwall on the the on Cornwall th e limits of of limits e , and an an and , ality. great height. height. great rose higher higher rose

- . to rage all rage to 3 feet higher higher 3 feet

….the ….the

th

0.63 - 0.09 - 0.49 - 0.55 - 2.15 0.66 - 2.36 - 1.96

(1901) Crossing (1901) Crossing (1888) Crossing (2012b) Horsham Archive; CBHE Dartmoor (1918) Worth (1901) Burnard (1896) Burnard ; CBHE

.

Accepted Article 1946 November 1944 November 1938 August 1930 August 1929 November June ? 1956/ 1959 August 1947

1970 1965

Dartmoor Venford Brook Venford O’ Brook, Dartmoor Bovey Dart, West Not stated Avon Dartmoor eastern and Central Dartmoor western & Southern Plym

B Ford Horse water. of the main down rolled villages boulders Dartmoor of number In a destroyed. bridge Dunnabridge Dartmoor. on at stations other many mm >120 totals and at Princetown fall daily Record Princetown. at mm 318 total of distances. considerable moved were tonnes several weighing boulders and livingin memory than higher was Avon River The hours. rain fell36 of in 155 mm 3 on Princetown at 62 mm of years. fall Daily claimed. bridges more Moor. Two lashed the storm A great beyond floods down bring to intense were sufficiently 68 mm 50 of but totals day, rainfall wasno outstanding There year. same the in of Aug& Oct mm and 112 mm 107 of Daily falls on 18 mm mm) 8 of excess in falls daily 4were 11 Between valley. the down water roared muddy of tons of thousands as intoadeath transformed was river stricken drought The cloudburst. a following floodwater wall of Plym River the when yesterday death escaped and children Women O’ Brook. on time at the photographed 0 oulder

mm at Princetown mm .

Two day total of 188 188 of day total Two

This articleis protected by copyright. All rightsreserved - normal.

berm deposited and deposited and berm

Greatest flood for 30 for flood Greatest streets with the rush thewith rush streets

th

was swept by a by swept was

& 19 & th destroyed

& 24 &

rd th of 173.5 mm mm 173.5 of .

November. November. th

there there (timber)

(2 >90 >90 (2 .

7 day 7 - - trap trap -

0.81 0.46 0.45 - 2.15 0.80 N/A 0.33 N/A 1.26 -

Worth (1945) Worth (1939) Worth (1978) Hemery (1931) Worth (1930) Worth (2012 Horsham (1978) Hemery CBHE Archive Dartmoor CBHE a

)

;

.

Accepted Article 1992 November 1979 December

East Dart Dart

Princetown. at rainfall 90 mm of daytotal 1992. and 1938, in 1890, bridge the over or flooded reached either have waters flood occasions least three atOn on 26 mm 90 of a max. with Princetown at mm 177 of day rainfall Two

This articleis protected by copyright. All rightsreserved spans (at (at Postbridge spans th .

2 - ), ), 4.52 2.07

(2004) Stanbrook Greeves and BADC

.