Deformation|NNP and|CC river|NN response|NN Before|IN specific|JJ examples|NNS of|IN syntectonic|JJ impacts|NNS on|IN alluvial|JJ rivers|NNS can|MD be|VB discussed|VBN ,|, a|DT brief|JJ review|NN of|IN types|NNS of|IN tectonic|JJ activity|NN ,|, types|NNS of|IN rivers|NNS ,|, and|CC river|NN response|NN will|MD be|VB presented|VBN .|. 
This|DT background|NN material|NN sets|VBZ the|DT stage|NN for|IN detailed|JJ discussions|NNS that|DT follow|VBP .|. 

Types|NNP of|IN deformation|NN The|DT surficial|NN movements|NNS in|IN an|DT alluvial|JJ valley|NN can|MD take|VB different|JJ forms|NNS ,|, as|IN illustrated|VBN in|IN Figure|NN 2.1|CD .|. 
The|DT displacement|NN can|MD be|VB seismic|JJ and|CC associated|VBN with|IN earthquakes|NNS and|CC abrupt|JJ faulting|VBG ,|, or|CC it|PRP can|MD be|VB aseismic|JJ with|IN progressive|JJ tilting|VBG and|CC warping|VBG of|IN the|DT valley|NN floor|NN .|. 
Faults|NNP may|MD be|VB lateral|NN faults|NNS that|WDT displace|VB or|CC offset|VBD the|DT channel|NN (|( Figure|NN 2.1|CD A|DT )|) without|IN vertical|JJ displacement|NN .|. 
This|DT type|NN of|IN displacement|NN should|MD be|VB easily|RB recognized|VBN .|. 
Faults|NNP with|IN vertical|JJ displacement|NN may|MD have|VB the|DT uplifted|JJ block|NN upstream|RB of|IN the|DT fault|NN with|IN the|DT result|NN that|DT gradient|NN is|VBZ steepened|JJ (|( Figure|NN 2.1|CD B|NNP )|) .|. 
In|IN the|DT opposite|JJ case|NN ,|, the|DT gradient|NN will|MD be|VB decreased|VBN (|( Figure|NN 2.1|CD C|NNP )|) .|. 
The|DT effect|NN will|MD resemble|VB monoclinal|NN tilting|VBG (|( Figure|NN 2.1|CD F|NN ,|, G|NNP )|) .|. 
Pairs|NNP of|IN faults|NNS may|MD produce|VB uplifted|JJ (|( horst|NN )|) or|CC downdropped|JJ blocks|NNS (|( graben|NN )|) that|WDT will|MD both|DT steepen|NN and|CC reduce|VB gradient|NN (|( Figure|NN 2.1|CD D|NNP ,|, E|NNP )|) .|. 
This|DT has|VBZ the|DT same|JJ effect|NN as|IN domes|NNS and|CC anticlines|NNS or|CC basins|NNS and|CC synclines|NNS (|( Figure|NN 2.1|CD H|NNP ,|, I|PRP )|) .|. 

In|IN addition|NN to|TO all|DT of|IN these|DT structural|JJ features|NNS ,|, the|DT entire|JJ valley|NN may|MD be|VB tilted|JJ upstream|RB or|CC downstream|JJ or|CC the|DT tilting|VBG may|MD be|VB across|IN the|DT valley|NN toward|IN either|DT side|NN of|IN the|DT floodplain|NN (|( Figure|NN 2.1|CD J|NNP ,|, K|NNP ,|, L|NNP )|) .|. 
The|DT possibilities|NNS are|VBP great|JJ ,|, but|CC in|IN reality|NN the|DT result|NN will|MD be|VB local|JJ steepening|VBG or|CC reduction|NN of|IN gradient|NN or|CC cross|JJ -|- valley|NN tilting|VBG .|. 

Streams|NNP respond|VBP to|TO vertical|JJ displacement|NN along|IN faults|NNS (|( Figure|NN 2.1|CD B|NNP and|CC C|NNP )|) by|IN aggradation|NN or|CC degradation|NN .|. 
When|WRB the|DT displacement|NN produces|VBZ a|DT channel|NN segment|NN steeper|JJR than|IN the|DT original|JJ stream|NN gradient|NN (|( Figure|NN 2.1|CD B|NNP )|) ,|, erosion|NN will|MD be|VB initiated|VBN in|IN this|DT reach|NN .|. 
When|WRB the|DT displacement|NN produces|VBZ a|DT channel|NN segment|NN of|IN lower|JJR elevation|NN or|CC gradient|NN than|IN the|DT original|JJ stream|NN (|( Figure|NN 2.1|CD C|NNP )|) ,|, aggradation|NN will|MD occur|VB .|. 
Even|RB small|JJ displacements|NNS may|MD be|VB sufficient|JJ to|TO induce|VB aggradation|NN or|CC degradation|NN of|IN large|JJ streams|NNS .|. 
If|IN the|DT displacement|NN forms|VBZ a|DT dam|NN (|( Figure|NN 2.1|CD C|NNP )|) ,|, the|DT stream|NN will|MD be|VB blocked|VBN ,|, and|CC it|PRP will|MD flow|VB along|IN the|DT fault|NN or|CC form|VB a|DT lake|NN .|. 
Wallace|NNP (|( 1968|CD )|) mentioned|VBN that|IN even|RB a|DT few|JJ inches|NNS of|IN vertical|JJ upthrow|NN along|IN the|DT downstream|JJ side|NN of|IN a|DT fault|NN can|MD produce|VB a|DT dam|NN across|IN a|DT small|JJ stream|NN ,|, which|WDT can|MD divert|VB its|PRP$ course|NN .|. 

NULL|NNP 
Figure|NN 2.1|CD Surface|NNP deformation|NN by|IN faulting|VBG ,|, folding|VBG ,|, and|CC lateral|NN tilting|VBG .|. Plan|NN view|NN on|IN left|VBD ;|: cross|JJ -|- section|NN on|IN right|NN (|( from|IN Ouchi|NNP ,|, 1983|CD )|) small|JJ arrows|NNS indicate|VBP direction|NN of|IN flow|NN .|. 
Large|JJ arrows|NNS indicate|VBP direction|NN of|IN movement|NN .|. 
The|DT displacement|NN in|IN each|DT case|NN is|VBZ greatly|RB exaggerated|JJ .|. 

Horst|NNP and|CC graben|NN (|( Figure|NN 2.1|CD D|NNP and|CC E|NNP )|) combine|VB two|CD different|JJ types|NNS of|IN vertical|JJ displacement|NN (|( Figure|NN 2.1|CD B|NNP and|CC C|NNP )|) .|. 
There|EX will|MD be|VB aggradation|NN upstream|RB from|IN the|DT horst|NN ,|, and|CC degradation|NN ,|, which|WDT will|MD migrate|VB upstream|RB ,|, on|IN the|DT downstream|JJ part|NN of|IN the|DT horst|NN .|. 
Reduced|NNP sediment|NN supply|NN because|IN of|IN aggradation|NN upstream|RB will|MD enhance|VB the|DT downstream|JJ degradation|NN .|. 
Upstream|NNP of|IN the|DT graben|NN ,|, there|EX will|MD be|VB degradation|NN and|CC aggradation|NN in|IN the|DT graben|NN itself|PRP .|. 
A|DT river|NN in|IN such|JJ a|DT location|NN will|MD be|VB unstable|JJ ,|, as|IN Cartier|NNP and|CC Alt|NNP (|( 1982|CD )|) suggested|VBD for|IN the|DT Bitterroot|NNP River|NNP in|IN Montana|NNP .|. 

The|DT type|NN of|IN folding|VBG (|( Figure|NN 2.1|CD )|) will|MD affect|VB a|DT river|NN similar|JJ to|TO the|DT various|JJ types|NNS of|IN faulting|VBG ,|, but|CC changes|NNS will|MD probably|RB be|VB less|RBR abrupt|JJ .|. 
The|DT effects|NNS of|IN tilting|VBG will|MD depend|VB upon|IN the|DT amount|NN ,|, but|CC in|IN the|DT simplest|JJS case|NN ,|, steepening|VBG of|IN a|DT valley|NN will|MD cause|VB degradation|NN (|( Figure|NN 2.1|CD K|NNP )|) and|CC a|DT reverse|NN tilt|NN (|( Figure|NN 2.1|CD L|NNP )|) will|MD cause|VB deposition|NN .|. 
Lateral|NNP tilting|VBG will|MD cause|VB channel|NN shift|NN downdip|NN (|( Figure|NN 2.1|CD J|NNP )|) or|CC avulsion|NN .|. 

Figure|NN 2.1|CD shows|VBZ only|RB simple|JJ ,|, but|CC exaggerated|JJ cases|NNS ,|, whereas|IN actual|JJ displacements|NNS can|MD be|VB more|RBR complicated|JJ .|. 
For|IN example|NN ,|, faults|NNS can|MD take|VB any|DT angle|NN from|IN parallel|JJ to|TO perpendicular|NN to|TO river|NN flow|NN direction|NN .|. 
Fault|NNP displacements|NNS of|IN the|DT surface|NN at|IN the|DT time|NN of|IN an|DT earthquake|NN are|VBP obvious|JJ ,|, and|CC its|PRP$ influence|NN on|IN alluvial|JJ rivers|NNS can|MD be|VB observed|VBN .|. 
For|IN example|NN ,|, small|JJ stream|NN channels|NNS have|VBP been|VBN offset|VBN by|IN strike|NN -|- slip|NN movement|NN (|( Figures|NNS 1.8|CD ,|, 2.1|CD A|DT )|) of|IN the|DT San|NNP Andreas|NNP fault|NN .|. 
Wallace|NNP (|( 1968|CD )|) pointed|VBD out|RP that|IN the|DT offset|VBN of|IN a|DT stream|NN channel|NN depends|VBZ on|IN the|DT relative|JJ rates|NNS of|IN fluvial|NN and|CC tectonic|JJ processes|NNS .|. 
The|DT main|JJ reason|NN why|WRB channel|NN offset|VBN caused|VBN by|IN the|DT San|NNP Andreas|NNP fault|NN is|VBZ clear|JJ is|VBZ the|DT extremely|RB high|JJ rate|NN of|IN displacement|NN along|IN the|DT fault|NN (|( 20.3|CD mm|NN /|NN year|NN ,|, Brown|NNP and|CC Wallace|NNP ,|, 1968|CD )|) and|CC the|DT relatively|RB small|JJ size|NN of|IN streams|NNS crossing|VBG and|CC flowing|VBG along|RB the|DT fault|NN .|. 
While|IN fault|NN displacements|NNS are|VBP obvious|JJ ,|, movements|NNS of|IN the|DT land|NN surface|NN by|IN folding|VBG can|MD be|VB slow|JJ .|. 
However|RB ,|, this|DT type|NN of|IN deformation|NN can|MD also|RB be|VB an|DT important|JJ influence|NN on|IN river|NN behavior|NN .|. 
For|IN example|NN ,|, concentration|NN of|IN erosion|NN along|IN only|RB one|CD river|NN bank|NN can|MD be|VB the|DT result|NN of|IN lateral|NN tilt|NN (|( Jefferson|NNP ,|, 1907|CD ;|: Nanson|NNP ,|, 1980|CD a|SYM ;|: Leeder|NNP and|CC Alexander|NNP ,|, 1987|CD )|) .|. 

Types|NNP of|IN alluvial|JJ rivers|NNS It|PRP is|VBZ apparent|JJ that|IN different|JJ types|NNS of|IN alluvial|JJ channels|NNS will|MD respond|VB differently|RB to|TO deformation|NN ;|: therefore|RB ,|, their|PRP$ characteristics|NNS must|MD be|VB reviewed|VBN before|IN their|PRP$ response|NN can|MD be|VB evaluated|VBN .|. 
This|DT can|MD best|JJS be|VB done|VBN by|IN discussing|VBG a|DT simple|JJ classification|NN of|IN alluvial|JJ channels|NNS that|WDT is|VBZ based|VBN on|IN type|NN of|IN sediment|NN load|NN and|CC pattern|NN .|. 

Five|CD basic|JJ channel|NN patterns|NNS exist|VBP (|( Figure|NN 2.2|CD )|) :|: (|( 1|CD )|) straight|JJ channels|NNS with|IN either|DT migrating|VBG sand|NN waves|NNS ;|: or|CC (|( 2|CD )|) with|IN migrating|VBG alternate|JJ bars|NNS forming|VBG a|DT sinuous|JJ thalweg|NN ;|: (|( 3|CD )|) two|CD types|NNS of|IN meandering|VBG channels|NNS ,|, a|DT highly|RB sinuous|JJ channel|NN of|IN equal|JJ width|NN (|( pattern|NN 3|CD a|DT )|) and|CC channels|NNS that|WDT are|VBP wider|JJR at|IN bends|NNS than|IN in|IN crossings|NNS (|( pattern|NN 3|CD b|SYM )|) ;|: (|( 4|CD )|) the|DT meandering|JJ –|- braided|JJ transition|NN ;|: and|CC (|( 5|CD )|) a|DT typical|JJ braided|JJ stream|NN .|. 
The|DT relative|JJ stability|NN of|IN these|DT channels|NNS in|IN terms|NNS of|IN their|PRP$ normal|JJ erosional|NN activity|NN and|CC the|DT shape|NN and|CC gradient|NN of|IN the|DT channels|NNS ,|, as|IN related|VBN to|TO relative|JJ sediment|NN size|NN ,|, load|NN ,|, velocity|NN of|IN flow|NN ,|, and|CC stream|NN power|NN ,|, are|VBP also|RB indicated|VBN in|IN Figure|NN 2.2|CD .|. 
It|PRP has|VBZ been|VBN possible|JJ to|TO develop|VB these|DT patterns|NNS experimentally|RB by|IN varying|VBG the|DT gradient|NN ,|, sediment|NN load|NN ,|, stream|NN power|NN ,|, and|CC the|DT type|NN of|IN sediment|NN load|NN transported|VBN by|IN the|DT channel|NN (|( Schumm|NNP and|CC Kahn|NNP ,|, 1972|CD )|) .|. 
Therefore|RB ,|, alluvial|JJ channels|NNS have|VBP also|RB been|VBN classified|VBN according|VBG to|TO the|DT type|NN of|IN sediment|NN load|NN moving|VBG through|IN the|DT channels|NNS ,|, as|IN suspended|JJ -|- load|NN ,|, mixed|JJ -|- load|NN ,|, and|CC bed|NN -|- load|NN channels|NNS (|( Figure|NN 2.2|CD )|) .|. 
Water|NNP discharge|NN determines|VBZ the|DT dimensions|NNS of|IN the|DT channel|NN (|( width|NN ,|, depth|NN ,|, meander|NN dimensions|NNS )|) ,|, but|CC the|DT relative|JJ proportions|NNS of|IN bed|NN load|NN (|( sand|NN and|CC gravel|NN )|) and|CC suspended|VBN load|NN (|( silts|NNS and|CC clays|NNS )|) determine|VB not|RB only|RB the|DT shape|NN of|IN the|DT channel|NN but|CC width|NN –|- depth|NN ratio|NN and|CC channel|NN pattern|NN .|. 
A|DT suspended|JJ -|- load|NN channel|NN has|VBZ been|VBN defined|VBN as|IN one|CD that|WDT transports|VBZ less|JJR than|IN 3|CD percent|NN bed|NN load|NN and|CC a|DT bed|NN -|- load|NN channel|NN as|IN one|CD transporting|VBG more|JJR than|IN 11|CD percent|NN bed|NN load|NN (|( Schumm|NNP ,|, 1977|CD )|) .|. 
The|DT mixed|JJ -|- load|NN channel|NN lies|VBZ between|IN these|DT two|CD (|( Figure|NN 2.2|CD )|) .|. 

NULL|NNP 
Figure|NN 2.2|CD Channel|NNP classification|NN based|VBN on|IN pattern|NN and|CC type|NN of|IN sediment|NN load|NN with|IN associated|VBN variables|NNS and|CC relative|JJ stability|NN indicated|VBD (|( Schumm|NNP ,|, 1981|CD )|) .|. 
Alluvial|NNP rivers|NNS that|WDT transport|NN clay|NN ,|, silt|NN ,|, sand|NN ,|, and|CC gravel|NN ,|, can|MD be|VB placed|VBN within|IN these|DT three|CD general|JJ categories|NNS .|. 
However|RB ,|, within|IN the|DT meandering|JJ -|- stream|NN group|NN there|EX is|VBZ considerable|JJ range|NN of|IN sinuosity|NN (|( 1.25|CD to|TO 3.0|CD )|) .|. 
In|IN addition|NN ,|, in|IN the|DT braided|JJ -|- stream|NN category|NN ,|, there|EX are|VBP bar|NN -|- braided|JJ and|CC island|NN -|- braided|JJ channels|NNS (|( islands|NNS are|VBP vegetated|JJ bars|NNS )|) .|. 

Figure|NN 2.2|CD suggests|VBZ that|IN the|DT range|NN of|IN channels|NNS from|IN straight|JJ to|TO braided|JJ forms|VBZ a|DT continuum|NN ,|, but|CC experimental|JJ work|NN and|CC field|NN studies|NNS have|VBP indicated|VBN that|IN the|DT changes|NNS of|IN pattern|NN between|IN braided|JJ ,|, meandering|VBG ,|, and|CC straight|JJ ,|, occur|VB relatively|RB abruptly|RB at|IN river|NN -|- pattern|NN thresholds|NNS (|( Figure|NN 2.3|CD )|) .|. 
The|DT pattern|NN changes|NNS take|VBP place|NN at|IN critical|JJ values|NNS of|IN stream|NN power|NN ,|, gradient|NN ,|, and|CC sediment|NN load|NN (|( Schumm|NNP and|CC Kahn|NNP ,|, 1972|CD )|) .|. 

NULL|NNP 
Figure|NN 2.3|CD Relation|NNP between|IN flume|NN slope|NN and|CC sinuosity|NN during|IN experiments|NNS at|IN constant|JJ water|NN discharge|NN .|. Sediment|NNP load|NN ,|, stream|NN power|NN ,|, velocity|NN increase|NN with|IN flume|NN slope|NN and|CC a|DT similar|JJ relation|NN can|MD be|VB developed|VBN with|IN these|DT variables|NNS (|( from|IN Schumm|NNP and|CC Khan|NNP ,|, 1972|CD )|) .|. 

Although|IN the|DT five|CD patterns|NNS of|IN Figure|NN 2.2|CD involve|VB all|DT three|CD river|NN types|NNS ,|, there|EX are|VBP five|CD basic|JJ bed|NN -|- load|NN channel|NN patterns|NNS (|( Figure|NN 2.4|CD A|DT )|) that|WDT have|VBP been|VBN recognized|VBN during|IN experimental|JJ studies|NNS of|IN channel|NN patterns|NNS (|( Schumm|NNP ,|, 1977|CD ,|, p.|NN 158|CD )|) .|. 
These|DT five|CD basic|JJ bed|NN -|- load|NN channel|NN patterns|NNS can|MD be|VB extended|VBN to|TO mixed|JJ -|- load|NN and|CC suspended|JJ -|- load|NN channels|NNS to|TO produce|VB 13|CD river|NN patterns|NNS (|( Figure|NN 2.4|CD )|) .|. 
Patterns|NNS 1|CD –|NN 5|CD are|VBP bed|NN -|- load|NN channel|NN patterns|NNS ,|, patterns|NNS 6|CD –|- 10|CD are|VBP mixed|JJ -|- load|NN |NN channel|NN patterns|NNS ,|, and|CC patterns|NNS 11|CD –|- 13|CD are|VBP suspended|JJ -|- load|NN channel|NN patterns|NNS .|. 
Figure|NN 2.4|CD attempts|NNS to|TO show|VB sinuosity|NN differences|NNS and|CC how|WRB the|DT pattern|NN thresholds|NNS change|VBP with|IN increasing|VBG valley|NN slope|NN ,|, stream|NN power|NN and|CC sediment|NN load|NN for|IN each|DT channel|NN type|NN .|. 
The|DT three|CD major|JJ river|NN types|NNS are|VBP controlled|VBN by|IN type|NN of|IN sediment|NN load|NN ,|, but|CC within|IN each|DT type|NN ,|, the|DT different|JJ patterns|NNS reflect|VBP increased|VBN valley|NN slope|NN ,|, sediment|NN load|NN ,|, and|CC stream|NN power|NN .|. 

The|DT different|JJ bed|NN -|- load|NN channel|NN patterns|NNS (|( Figure|NN 2.4|CD )|) can|MD be|VB described|VBN as|IN follows|VBZ :|: Pattern|NNP 1|CD ,|, straight|JJ ,|, essentially|RB equal|JJ -|- width|NN channel|NN with|IN migrating|VBG sand|NN waves|NNS .|. 
Pattern|NNP 2|CD ,|, alternate|JJ -|- bar|NN channel|NN with|IN migrating|VBG side|NN or|CC alternate|JJ bars|NNS and|CC a|DT slightly|RB sinuous|JJ thalweg|NN ;|: Pattern|NNP 3|CD ,|, low|JJ -|- sinuosity|NN meandering|VBG channel|NN with|IN large|JJ alternate|JJ bars|NNS that|WDT develop|VBP chutes|NNS ;|: Pattern|NNP 4|CD ,|, transitional|JJ meandering|JJ -|- thalweg|NN braided|JJ channel|NN .|. 
The|DT large|JJ alternate|JJ bars|NNS or|CC point|NN bars|NNS have|VBP been|VBN dissected|VBN by|IN chutes|NNS ,|, but|CC a|DT meandering|VBG thalweg|NN can|MD be|VB identified|VBN .|. 
Pattern|NNP 5|CD is|VBZ a|DT typical|JJ bar|NN -|- braided|JJ channel|NN .|. 

As|IN compared|VBN to|TO the|DT bed|NN -|- load|NN channels|NNS ,|, the|DT five|CD mixed|JJ -|- load|NN channels|NNS (|( Figure|NN 2.4|CD B|NNP )|) are|VBP relatively|RB narrower|JJR and|CC deeper|JJR ,|, and|CC there|EX is|VBZ greater|JJR bank|NN stability|NN .|. 
The|DT higher|JJR degree|NN of|IN bank|NN stability|NN permits|VBZ the|DT maintenance|NN of|IN narrow|JJ ,|, deep|JJ ,|, straight|JJ channels|NNS (|( Pattern|NNP 6|CD )|) ,|, and|CC alternate|JJ bars|NNS stabilize|VBP because|IN of|IN the|DT finer|NN sediments|NNS to|TO form|VB slightly|RB sinuous|JJ channels|NNS (|( Pattern|NNP 7|CD )|) .|. 
Pattern|NNP 8|CD is|VBZ a|DT truly|RB meandering|VBG channel|NN ,|, wide|JJ on|IN the|DT bends|NNS ,|, relatively|RB narrow|JJ at|IN the|DT crossings|NNS ,|, and|CC subject|JJ to|TO chute|NN cutoffs|NNS .|. 
Pattern|NNP 9|CD maintains|VBZ the|DT sinuosity|NN of|IN a|DT meandering|VBG channel|NN ,|, but|CC with|IN a|DT greater|JJR sediment|NN transport|NN the|DT presence|NN of|IN bars|NNS gives|VBZ it|PRP a|DT composite|JJ sinuous|JJ -|- braided|JJ appearance|NN .|. 
Pattern|NNP 10|CD is|VBZ a|DT braided|JJ channel|NN that|WDT is|VBZ relatively|RB more|RBR stable|JJ than|IN that|DT of|IN bed|NN -|- load|NN channel|NN 5|CD ,|, and|CC it|PRP is|VBZ likely|JJ to|TO be|VB island|NN -|- braided|JJ .|. 

NULL|NNP 
Figure|NN 2.4|CD The|DT range|NN of|IN alluvial|JJ channel|NN patterns|NNS for|IN the|DT three|CD channel|NN types|NNS :|: (|( A|DT )|) bed|NN -|- load|NN channel|NN patterns|NNS ,|, (|( B|NNP )|) mixed|JJ -|- load|NN channel|NN patterns|NNS ,|, (|( C|NNP )|) suspended|JJ -|- load|NN channel|NN patterns|NNS (|( from|IN Schumm|NNP ,|, 1981|CD )|) .|. 
Suspended|JJ -|- load|NN channels|NNS (|( Figure|NN 2.4|CD C|NNP )|) are|VBP narrow|JJ and|CC deeper|JJR than|IN mixed|JJ -|- load|NN channels|NNS .|. 
Suspended|NNP load|NN Pattern|NNP 11|CD is|VBZ a|DT straight|JJ ,|, narrow|JJ ,|, deep|JJ channel|NN .|. 
With|IN only|RB small|JJ quantities|NNS of|IN bed|NN load|NN ,|, this|DT type|NN of|IN channel|NN may|MD have|VB the|DT highest|JJS sinuosity|NN of|IN all|DT (|( Patterns|NNS 12|CD and|CC 13|CD )|) .|. 

Rivers|NNP may|MD undergo|VB a|DT metamorphosis|NNS during|IN which|WDT the|DT channel|NN morphology|NN changes|NNS completely|RB .|. 
That|DT is|VBZ ,|, a|DT suspended|JJ -|- load|NN channel|NN (|( Pattern|NNP 12|CD )|) could|MD become|VB braided|JJ (|( Pattern|NNP 5|CD )|) ,|, or|CC a|DT braided|JJ channel|NN (|( Pattern|NNP 5|CD )|) could|MD become|VB meandering|VBG (|( Pattern|NNP 8|CD or|CC 12|CD )|) ,|, etc.|NN 
,|, when|WRB there|EX is|VBZ a|DT sufficiently|RB great|JJ change|NN in|IN the|DT type|NN of|IN sediment|NN load|NN transported|VBN through|IN that|DT channel|NN .|. 
Therefore|RB ,|, the|DT change|NN from|IN one|CD type|NN of|IN channel|NN pattern|NN to|TO another|DT may|MD be|VB relatively|RB common|JJ ,|, as|IN the|DT nature|NN of|IN the|DT sediment|NN moved|VBD through|IN the|DT system|NN changes|NNS and|CC this|DT may|MD be|VB the|DT effect|NN of|IN tributary|JJ sediment|NN contributions|NNS ,|, or|CC upstream|RB degradation|NN or|CC aggradation|NN or|CC tectonics|NNS .|. 

There|EX is|VBZ an|DT additional|JJ channel|NN pattern|NN that|IN spans|NNS the|DT range|NN of|IN stream|NN types|NNS of|IN Figure|NN 2.4|CD .|. 
This|DT is|VBZ the|DT anastomosing|VBG pattern|NN of|IN branching|VBG and|CC rejoining|VBG channel|NN segments|NNS (|( Schumm|NNP et|CC al.|NN ,|, 1996|CD )|) .|. 
The|DT channel|NN segments|NNS can|MD be|VB straight|JJ ,|, meandering|VBG ,|, or|CC braided|JJ ,|, and|CC they|PRP appear|VBP to|TO span|NN the|DT range|NN of|IN channel|NN types|NNS .|. 
Anastomosing|NNP or|CC anabranching|VBG channels|NNS differ|VBP from|IN braided|JJ channels|NNS because|IN they|PRP are|VBP composed|VBN of|IN multiple|JJ channels|NNS that|WDT are|VBP separated|VBN by|IN a|DT floodplain|NN (|( Figure|NN 2.5|CD )|) ,|, whereas|IN braided|JJ channels|NNS have|VBP multiple|JJ thalwegs|NNS in|IN a|DT single|JJ channel|NN .|. 
Knighton|NNP and|CC Nanson|NNP (|( 1993|CD )|) and|CC Richards|NNP et|CC al.|NN (|( 1993|CD )|) suggest|VBP that|IN this|DT pattern|NN is|VBZ transitioned|JJ to|TO a|DT single|JJ channel|NN because|IN anastomosing|VBG rivers|NNS appear|VBP to|TO be|VB associated|VBN with|IN partly|RB blocked|VBN valleys|NNS (|( Smith|NNP and|CC Smith|NNP ,|, 1980|CD )|) and|CC tectonic|JJ uplift|NN (|( Gregory|NNP and|CC Schumm|NNP ,|, 1987|CD )|) .|. 
Reduced|NNP gradient|NN from|IN whatever|WDT cause|VBP appears|VBZ to|TO be|VB important|JJ ,|, and|CC therefore|RB ,|, anastomosing|VBG reaches|NNS of|IN a|DT river|NN can|MD be|VB evidence|NN of|IN tectonic|JJ activity|NN .|. 

Evidence|NN of|IN deformation|NN The|DT first|JJ geomorphic|JJ clues|NNS of|IN active|JJ tectonics|NNS may|MD be|VB tectonic|JJ landforms|NNS that|WDT result|NN from|IN long|JJ -|- continued|JJ deformation|NN such|JJ as|IN modified|VBN drainage|NN networks|NNS and|CC deformed|VBN sets|NNS of|IN terraces|NNS .|. 
These|DT obvious|JJ features|NNS are|VBP in|IN contrast|NN to|TO the|DT more|RBR subtle|JJ changes|NNS of|IN alluvial|JJ rivers|NNS .|. 

Drainage|NNP networks|NNS The|DT arrangement|NN of|IN streams|NNS and|CC tributaries|NNS into|IN a|DT drainage|NN network|NN is|VBZ affected|VBN by|IN the|DT regional|JJ slope|NN of|IN the|DT surface|NN on|IN which|WDT the|DT pattern|NN develops|VBZ ,|, climate|NN ,|, and|CC the|DT erodibility|NN of|IN the|DT surface|NN material|NN .|. 
Local|JJ variations|NNS in|IN both|DT slope|NN and|CC materials|NNS will|MD cause|VB variations|NNS in|IN the|DT drainage|NN pattern|NN (|( Figure|NN 1.2|CD )|) .|. 
For|IN example|NN ,|, experimental|JJ studies|NNS demonstrated|VBN that|IN parallel|JJ drainage|NN patterns|NNS form|VBP on|IN slopes|NNS greater|JJR than|IN about|IN 2.5|CD percent|NN ,|, whereas|IN dendritic|JJ patterns|NNS form|VBP on|IN gentler|JJR slopes|NNS (|( Phillips|NNP and|CC Schumm|NNP ,|, 1987|CD )|) .|. 

NULL|NNP 
Figure|NN 2.5|CD Map|NNP of|IN anastomosing|VBG channels|NNS of|IN Ovens|NNP and|CC King|NNP Rivers|NNP .|. Numbers|NNPS indicate|VBP relative|JJ ages|NNS of|IN channels|NNS and|CC reaches|NNS of|IN channels|NNS from|IN youngest|JJS (|( 1|CD )|) to|TO oldest|JJS (|( 4|CD )|) (|( from|IN Schumm|NNP et|CC al.|NN ,|, 1996|CD )|) .|. 

Local|JJ variations|NNS in|IN regional|JJ surface|NN slope|NN can|MD cause|VB anomalous|JJ drainage|NN patterns|NNS .|. 
A|DT topographic|JJ high|RB caused|VBN by|IN active|JJ uplift|NN ,|, will|MD cause|VB a|DT deflection|NN of|IN portions|NNS of|IN the|DT drainage|NN pattern|NN .|. 
For|IN instance|NN ,|, on|IN the|DT upslope|NN side|NN of|IN an|DT uplift|NN the|DT local|JJ surface|NN slope|NN will|MD be|VB opposite|JJ that|IN of|IN the|DT regional|JJ slope|NN .|. 
This|DT can|MD cause|VB portions|NNS of|IN the|DT drainage|NN pattern|NN to|TO develop|VB in|IN a|DT direction|NN opposite|JJ to|TO that|DT of|IN the|DT drainage|NN network|NN .|. 
An|DT uplift|NN may|MD also|RB deflect|VB portions|NNS of|IN the|DT drainage|NN from|IN the|DT general|JJ direction|NN of|IN the|DT regional|JJ slope|NN (|( Figure|NN 2.6|CD )|) .|. 
As|IN the|DT major|JJ streams|NNS are|VBP deflected|VBD away|RB from|IN the|DT uplift|NN ,|, tributaries|NNS on|IN one|CD side|NN will|MD be|VB lengthened|VBN and|CC those|DT on|IN the|DT other|JJ side|NN will|MD be|VB shortened|VBN .|. 

Changes|NNS of|IN an|DT entire|JJ drainage|NN network|NN ,|, as|IN a|DT result|NN of|IN tilting|VBG ,|, are|VBP described|VBN by|IN Sparling|NNP (|( 1967|CD )|) who|WP notes|VBZ that|IN isostatic|JJ adjustment|NN in|IN Ottawa|NNP County|NNP ,|, Ohio|NNP has|VBZ increased|VBN the|DT gradient|NN of|IN some|DT streams|NNS and|CC decreased|VBD the|DT gradient|NN of|IN others|NNS .|. 
Incision|NNP of|IN the|DT steepened|JJ streams|NNS permitted|VBD them|PRP to|TO capture|VB the|DT streams|NNS that|WDT were|VBD aggrading|VBG as|IN a|DT result|NN of|IN reduced|VBN gradient|NN .|. 
Russell|NNP (|( 1939|CD )|) described|VBD various|JJ drainage|NN patterns|NNS found|VBD in|IN the|DT flat|JJ alluvial|JJ lands|NNS of|IN Louisiana|NNP ,|, and|CC he|PRP recognized|VBD a|DT network|NN pattern|NN of|IN poorly|RB developed|VBN drainage|NN channels|NNS that|WDT was|VBD converted|VBN to|TO a|DT dendritic|JJ pattern|NN ,|, as|IN a|DT result|NN of|IN tilting|VBG and|CC steepening|VBG of|IN the|DT gradient|NN .|. 

NULL|NNP 
Figure|NN 2.6|CD Drainage|NNP pattern|NN modified|VBN by|IN uplift|NN .|. 
Price|NNP and|CC Whetstone|NNP (|( 1977|CD )|) used|VBN asymmetric|JJ river|NN and|CC valley|NN cross|JJ -|- section|NN profiles|NNS ,|, as|IN evidence|NN for|IN movement|NN along|IN the|DT Chattahoochee|NNP Embayment|NNP in|IN Florida|NNP .|. 
Subsidence|NNP caused|VBD southward|NN migration|NN of|IN east–west|NN flowing|VBG channels|NNS .|. 
South|JJ -|- flowing|JJ streams|NNS exhibit|NN paired|VBN terraces|NNS while|IN east–west|NN trending|VBG streams|NNS contain|VBP extensive|JJ terraces|NNS on|IN the|DT northern|JJ side|NN with|IN few|JJ or|CC no|DT terraces|NNS on|IN the|DT steeper|JJR southern|JJ margin|NN .|. 
Subsidence|NNP in|IN the|DT Chattahoochee|NNP Embayment|NNP and|CC adjacent|JJ warping|VBG along|RB the|DT Chattahoochee|NNP Uplift|NNP resulted|VBD in|IN asymmetrical|JJ incision|NN along|IN the|DT Chattahoochee|NNP River|NNP .|. 

Long|JJ -|- continued|JJ tilting|VBG in|IN a|DT cross|JJ -|- valley|NN direction|NN will|MD cause|VB lateral|NN erosion|NN and|CC the|DT development|NN of|IN an|DT asymmetrical|JJ valley|NN and|CC drainage|NN network|NN .|. 
Muehlberger|NNP (|( 1979|CD )|) noted|VBD this|DT type|NN of|IN asymmetry|NN in|IN an|DT area|NN near|IN Taos|NNP ,|, New|NNP Mexico|NNP (|( Figure|NN 2.7|CD )|) .|. 
Using|VBG 71|CD ⁄|NN minute|NN U.S.|NNP Geological|NNP Survey|NNP topographic|JJ 
2|CD maps|NNS ,|, he|PRP described|VBD this|DT asymmetry|NN quantitatively|RB .|. 
By|IN selecting|VBG a|DT contour|NN on|IN the|DT valley|NN wall|NN and|CC measuring|VBG the|DT distance|NN from|IN the|DT stream|NN to|TO this|DT contour|NN in|IN a|DT down|IN -|- tilt|NN direction|NN (|( Dd|NNP )|) and|CC in|IN the|DT opposite|NN ,|, uptilt|NN direction|NN (|( Du|NNP )|) an|DT index|NN of|IN asymmetry|NN was|VBD developed|VBN (|( Dd|NNP /|NN Du|NNP )|) (|( Figure|NN 2.7|CD )|) .|. 
The|DT index|NN for|IN 30|CD small|JJ drainage|NN basins|NNS was|VBD 0.6|CD indicating|VBG a|DT major|JJ displacement|NN of|IN the|DT main|JJ channel|NN in|IN a|DT down|IN -|- tilt|NN direction|NN .|. 
Cox|NNP (|( 1994|CD )|) used|VBD a|DT somewhat|RB different|JJ index|NN to|TO demonstrate|VB tilting|VBG and|CC river|NN shift|NN in|IN the|DT southwestern|JJ Mississippi|NNP Embayment|NNP .|. 
Other|JJ indices|NNS of|IN asymmetry|NN are|VBP described|VBN by|IN Keller|NNP and|CC Pinter|NNP (|( 1996|CD ,|, pp.|NN 126|CD ,|, 127|CD )|) .|. 

NULL|NNP 
Figure|NN 2.7|CD Map|NNP of|IN asymmetrical|JJ stream|NN valleys|NNS in|IN the|DT vicinity|NN of|IN Taos|NNP ,|, New|NNP Mexico|NNP showing|VBG method|NN of|IN measuring|VBG distances|NNS used|VBN in|IN calculating|VBG index|NN of|IN asymmetry|NN (|( modified|VBN after|IN Muehlberger|NNP ,|, 1979|CD )|) .|. 

Lake|NNP patterns|NNS Lakes|NNP are|VBP temporary|JJ features|NNS in|IN terms|NNS of|IN geological|JJ time|NN ,|, but|CC they|PRP can|MD be|VB clear|JJ evidence|NN of|IN deformation|NN .|. 
They|PRP occur|VBP at|IN various|JJ scales|NNS ,|, along|IN primary|JJ or|CC secondary|JJ portions|NNS of|IN the|DT drainage|NN network|NN ,|, and|CC generally|RB disappear|VB as|IN erosion|NN and|CC deposition|NN occurs|VBZ through|IN time|NN .|. 
They|PRP may|MD be|VB isolated|VBN ,|, but|CC they|PRP are|VBP more|RBR frequently|RB clustered|VBN in|IN a|DT specific|JJ area|NN ,|, or|CC they|PRP are|VBP aligned|VBN along|IN specific|JJ trends|NNS .|. 
Isolated|NNP lakes|NNS are|VBP generally|RB due|JJ to|TO local|JJ events|NNS such|JJ as|IN landslides|NNS or|CC collapses|VBZ ,|, which|WDT form|VBP a|DT dam|NN ,|, but|CC clustered|VBN lakes|NNS are|VBP due|JJ to|TO regional|JJ processes|NNS ,|, which|WDT may|MD be|VB related|VBN to|TO climate|NN (|( or|CC paleoclimate|NN )|) ,|, neotectonic|JJ deformation|NN ,|, or|CC frequently|RB a|DT combination|NN of|IN these|DT processes|NNS .|. 

Large|JJ lakes|NNS may|MD occupy|VB geological|JJ basins|NNS ,|, and|CC active|JJ tectonics|NNS is|VBZ partly|RB or|CC totally|RB involved|VBN in|IN their|PRP$ formation|NN .|. 
Such|JJ lakes|NNS act|VBP as|IN drainage|NN collectors|NNS and|CC they|PRP can|MD occupy|VB various|JJ elevations|NNS .|. 
The|DT Bolivian|NNP Altiplano|NNP lakes|NNS (|( Titicaca|NNP ,|, Popoo|NNP ,|, Uyuni|NNP )|) stand|VB at|IN an|DT elevation|NN of|IN around|IN 4000|CD m|NN and|CC are|VBP associated|VBN with|IN plate|NN convergence|NN and|CC uplift|NN .|. 
Continental|NNP stretching|VBG and|CC transtensional|NN tectonics|NNS are|VBP favorable|JJ for|IN the|DT formation|NN of|IN basins|NNS and|CC tectonic|JJ lakes|NNS .|. 
Often|RB the|DT relation|NN of|IN lakes|NNS to|TO faults|NNS is|VBZ obvious|JJ ,|, and|CC a|DT study|NN of|IN the|DT lake|NN pattern|NN is|VBZ not|RB necessary|JJ to|TO demonstrate|VB the|DT effect|NN of|IN tectonics|NNS .|. 
(|( See|VB Chapter|NN 5|CD where|WRB Reelfoot|NNP Lake|NNP and|CC the|DT Mississippi|NNP valley|NN sunklands|NNS are|VBP described|VBN ;|: Figures|NNS 5.1|CD ,|, 5.2|CD )|) .|. 

NULL|NNP 
Figure|NN 2.8|CD Inferred|NNP fault|NN zone|NN in|IN the|DT area|NN of|IN the|DT Tupinambaranas|NNP ,|, in|IN the|DT Amazon|NNP Basin|NNP between|IN Obidos|NNP and|CC Manaus|NNP Brazil|NNP (|( modified|VBN after|IN Sternberg|NNP ,|, 1955|CD )|) .|. The|DT river|NN trace|VB and|CC ria|NN lakes|NNS suggest|VBP a|DT downward|JJ movement|NN along|IN the|DT same|JJ axis|NNS as|IN that|DT of|IN the|DT inferred|VBN fault|NN .|. 

This|DT discussion|NN deals|NNS with|IN cases|NNS where|WRB specific|JJ lake|NN patterns|NNS ,|, (|( ria|NN lakes|NNS and|CC elongated|JJ lakes|NNS )|) ,|, are|VBP related|VBN to|TO active|JJ deformation|NN .|. 
Most|JJS of|IN these|DT concepts|NNS are|VBP not|RB new|JJ .|. 
For|IN example|NN ,|, the|DT significance|NN of|IN ria|NN lakes|NNS was|VBD identified|VBN more|JJR than|IN 30|CD years|NNS ago|RB .|. 

Ria|NNP Lakes|NNP Dendritic|NNP ria|NN lakes|NNS occur|VBP at|IN the|DT lower|JJR part|NN of|IN a|DT tributary|JJ ,|, which|WDT is|VBZ blocked|VBN by|IN aggradation|NN along|IN the|DT trunk|NN river|NN (|( Holz|NNP et|CC al.|NN ,|, 1979|CD )|) .|. 
In|IN the|DT lower|JJR and|CC central|JJ parts|NNS of|IN the|DT Amazonian|JJ Basin|NNP the|DT formation|NN of|IN ria|NN lakes|NNS is|VBZ related|VBN to|TO post-glacial|JJ eustacy|NN (|( Irion|NNP ,|, 1984|CD )|) .|. 
Some|DT of|IN these|DT lakes|NNS have|VBP a|DT “|NN knee|NN ”|NN pattern|NN superposed|JJ on|IN the|DT dendritic|JJ pattern|NN suggesting|VBG the|DT effect|NN of|IN active|JJ faulting|VBG through|IN a|DT thick|JJ sedimentary|JJ cover|NN (|( Sternberg|NNP ,|, 1950|CD ,|, 1955|CD ,|, Figure|NN 2.8|CD )|) .|. 

NULL|NNP 
Figure|NN 2.9|CD Structural|NNP scheme|NN of|IN the|DT Marañón|NNP Basin|NNP in|IN Peru|NNP ,|, composed|VBN of|IN the|DT Pastaza|NNP Basin|NNP and|CC the|DT Ucamara|NNP Depression|NNP .|. Stars|NNP show|NN the|DT location|NN of|IN the|DT main|JJ ria|NN lakes|NNS ,|, with|IN the|DT area|NN A|DT represented|VBD in|IN detail|NN .|. 
The|DT contour|NN lines|NNS show|VBP the|DT isobath|NN of|IN the|DT pre-Jurassic|JJ basement|NN ,|, from|IN Sanz|NNP (|( 1974|CD )|) .|. 
Section|NN along|IN X|NNP –|- Y|NNP in|IN the|DT lower|JJR part|NN of|IN the|DT figure|NN ,|, modified|VBN after|IN Laurent|NNP (|( 1985|CD )|) .|. 

Reservoirs|NNP behind|IN dams|NNS take|VBP the|DT form|NN of|IN ria|NN lakes|NNS .|. 
Clusters|NNP of|IN ria|NN lakes|NNS are|VBP observed|VBN along|IN large|JJ rivers|NNS in|IN the|DT western|JJ Marañón|NNP Basin|NNP and|CC in|IN the|DT central|JJ Ucayali|NNP Basin|NNP ,|, Peru|NNP (|( Räsänen|NNP et|CC al.|NN ,|, 1987|CD ;|: Dumont|NNP ,|, 1993|CD )|) .|. 
They|PRP are|VBP related|VBN to|TO active|JJ subsidence|NN of|IN the|DT back|NN side|NN of|IN piggy|NN back|RB or|CC thrust|NN faults|NNS .|. 
Similar|JJ patterns|NNS are|VBP observed|VBN on|IN the|DT south|NN margin|NN of|IN the|DT Beni|NNP Basin|NNP (|( Dumont|NNP ,|, 1992|CD ;|: Dumont|NNP and|CC Guyot|NNP ,|, 1993|CD )|) .|. 

An|DT elongated|JJ cluster|NN of|IN ria|NN lakes|NNS is|VBZ located|VBN along|IN the|DT lower|JJR Pastaza|NNP River|NNP and|CC the|DT Marañón|NNP River|NNP in|IN the|DT western|JJ part|NN of|IN the|DT Marañón|NNP Basin|NNP (|( Figure|NN 2.9|CD )|) .|. 
This|DT cluster|NN is|VBZ superimposed|VBN over|IN the|DT structural|JJ axis|NNS of|IN the|DT basin|NN ,|, which|WDT trends|NNS toward|IN the|DT Ucamara|NNP Depression|NNP .|. 
This|DT axis|NNS of|IN maximum|NN subsidence|NN of|IN the|DT basin|NN is|VBZ located|VBN in|IN front|NN of|IN the|DT Subandean|NNP Thrust|NNP and|CC Fault|NNP Belt|NNP (|( STFB|NNP )|) .|. 

NULL|NNP 
Figure|NN 2.10|CD Relative|NNP positions|NNS of|IN tectonic|JJ lakes|NNS in|IN the|DT Peruvian|JJ foreland|NN basins|NNS .|. Stars|NNP indicate|VBP location|NN of|IN clusters|NNS of|IN ria|NN lakes|NNS (|( modified|VBN after|IN Dumont|NNP ,|, 1996|CD )|) .|. 

The|DT Pastaza|NNP depression|NN is|VBZ filled|VBN by|IN more|JJR than|IN 4|CD 500|CD m|NN of|IN Cretaceous|JJ and|CC Cenozoic|NNP sediments|NNS ,|, with|IN about|IN 500|CD m|NN of|IN Quaternary|NNP sediment|NN (|( Laurent|NNP ,|, 1985|CD )|) (|( Figure|NN 2.9|CD )|) .|. 
No|DT ria|NN lakes|NNS are|VBP observed|VBN in|IN the|DT south|NN part|NN of|IN the|DT Marañón|NNP Basin|NNP (|( Ucamara|NNP Depression|NNP )|) ,|, but|CC ria|NN lakes|NNS occur|VBP again|RB in|IN the|DT Ucayali|NNP Basin|NNP of|IN Central|NNP Peru|NNP (|( Figure|NN 2.10|CD )|) ,|, a|DT piggy|JJ -|- back|RP basin|NN .|. 

A|DT continental|JJ rift|NN generates|VBZ tilt|NN of|IN the|DT side|NN blocks|NNS in|IN opposite|JJ directions|NNS and|CC the|DT progressive|JJ tilting|VBG of|IN the|DT earth|NN ’|NN s|VBZ surface|NN can|MD significantly|RB modify|VB the|DT gradient|NN of|IN rivers|NNS .|. 
For|IN example|NN ,|, Lake|NNP Victoria|NNP is|VBZ drained|VBN by|IN the|DT Victoria|NNP Nile|NNP which|WDT flows|NNS north|RB to|TO Lake|NNP Kyoga|NNP (|( Figure|NN 2.11|CD )|) .|. 
Lake|NNP Kyoga|NNP and|CC Lake|NNP Kwania|NNP look|VB artificial|JJ ,|, but|CC they|PRP are|VBP not|RB the|DT result|NN of|IN dam|NN construction|NN .|. 
They|PRP are|VBP ,|, in|IN fact|NN ,|, formed|VBN by|IN uplift|NN and|CC eastward|RB tilting|VBG of|IN western|JJ Uganda|NNP .|. 
Flow|NNP in|IN the|DT Kafu|NNP River|NNP has|VBZ been|VBN reversed|VBN ,|, and|CC water|NN draining|VBG from|IN Lake|NNP Victoria|NNP has|VBZ found|VBN a|DT new|JJ course|NN to|TO the|DT north|NN ,|, where|WRB it|PRP flows|VBZ over|IN Murchison|NNP Falls|NNP and|CC into|IN Lake|NNP Albert|NNP .|. 
The|DT geologically|RB recent|JJ derangement|NN of|IN these|DT drainage|NN systems|NNS is|VBZ the|DT result|NN of|IN uplift|NN that|WDT is|VBZ apparently|RB continuing|VBG at|IN the|DT present|JJ time|NN (|( Doornkamp|NNP and|CC Temple|NNP ,|, 1966|CD )|) .|. 

NULL|NNP 
Figure|NN 2.11|CD Lake|NNP Kyoga|NNP region|NN ,|, Uganda|NNP .|. Arrows|NNP show|NN flow|NN directions|NNS in|IN rivers|NNS .|. 
Back|RB tilting|VBG explains|VBZ the|DT shape|NN of|IN Lake|NNP Kyoga|NNP and|CC Lake|NNP Kwania|NNP (|( modified|VBN after|IN Doornkamp|NNP and|CC Temple|NNP ,|, 1966|CD )|) .|. 

Elongated|NNP lakes|NNS The|DT term|NN elongated|JJ lakes|NNS is|VBZ applied|VBN to|TO lakes|NNS that|WDT are|VBP long|JJ and|CC narrow|JJ .|. 
These|DT lakes|NNS are|VBP superimposed|VBN over|IN basement|NN structures|NNS .|. 
In|IN subsiding|VBG basins|NNS ,|, they|PRP are|VBP also|RB closely|RB related|VBN to|TO active|JJ tectonics|NNS .|. 

The|DT Puinahua|NNP (|( 1324|CD km2|NN )|) and|CC Punga|NNP (|( 341|CD km2|NN )|) lakes|NNS are|VBP both|DT located|VBN in|IN the|DT south|NN part|NN of|IN the|DT Marañón|NNP Basin|NNP (|( Figure|NN 2.10|CD )|) .|. 
They|PRP are|VBP long|JJ and|CC narrow|JJ and|CC wider|RBR on|IN the|DT foothill|NN side|NN than|IN on|IN the|DT craton|NN side|NN .|. 
Punga|NNP Lake|NNP is|VBZ superimposed|VBN over|IN the|DT structure|NN of|IN the|DT Santa|NNP Elena|NNP uplift|NN (|( Dumont|NNP and|CC Garcia|NNP ,|, 1991|CD )|) ,|, which|WDT is|VBZ interpreted|VBN as|IN a|DT crystalline|JJ horst|NN surrounded|VBN by|IN Paleozoic|NNP sedimentary|JJ strata|NN (|( Laurent|NNP ,|, 1985|CD )|) .|. 
The|DT NE|NNP elongation|NN of|IN the|DT lake|NN is|VBZ parallel|JJ to|TO a|DT few|JJ of|IN the|DT structural|JJ features|NNS mentioned|VBN by|IN Laurent|NNP (|( 1985|CD )|) .|. 
Both|DT lakes|NNS are|VBP also|RB parallel|JJ to|TO the|DT strike|NN of|IN normal|JJ faulting|VBG with|IN a|DT NNW–SSE|NNP extension|NN in|IN the|DT upland|NN border|NN (|( Dumont|NNP et|CC al.|NN ,|, 1988|CD )|) .|. 
As|IN a|DT result|NN ,|, the|DT lakes|NNS are|VBP interpreted|VBN as|IN the|DT surface|NN expression|NN of|IN tensional|NN stress|NN superimposed|VBN over|IN reactivated|VBD basement|NN structures|NNS due|JJ to|TO the|DT onset|NN of|IN Andean|JJ tectonics|NNS (|( Dumont|NNP and|CC Garcia|NNP ,|, 1991|CD )|) .|. 

More|RBR precise|JJ morphological|JJ evidence|NN of|IN active|JJ tectonics|NNS comes|VBZ from|IN the|DT Punga|NNP Lake|NNP .|. 
According|VBG to|TO testimony|NN of|IN old|JJ settlers|NNS and|CC published|VBN travel|NN journals|NNS (|( Stiglish|NNP ,|, 1904|CD )|) the|DT area|NN was|VBD covered|VBN by|IN forest|NN ,|, that|WDT developed|VBD on|IN a|DT terrace|NN before|IN 1923|CD .|. 
Then|RB the|DT region|NN began|VBD to|TO subside|NN .|. 
The|DT tree|NN trunks|NNS of|IN the|DT drowned|VBN forest|NN are|VBP still|RB visible|JJ ,|, now|RB below|IN 2|CD m|NN of|IN water|NN during|IN low|JJ water|NN stages|NNS .|. 
In|IN this|DT very|RB flat|JJ area|NN the|DT water|NN level|NN rises|VBZ about|IN 2|CD m|NN during|IN floods|NNS ,|, suggesting|VBG a|DT minimum|JJ subsidence|NN of|IN 4|CD m|NN over|IN about|IN 70|CD years|NNS .|. 
A|DT tectonic|JJ interpretation|NN is|VBZ favored|VBN because|IN a|DT local|JJ rise|NN of|IN base|NN level|NN cannot|NN be|VB involved|VBN .|. 
Only|RB a|DT downward|JJ motion|NN of|IN the|DT area|NN where|WRB the|DT lake|NN is|VBZ observed|VBN can|MD explain|VB the|DT phenomenon|NN .|. 
These|DT lakes|NNS are|VBP related|VBN to|TO downdropped|JJ blocks|NNS that|WDT are|VBP related|VBN to|TO a|DT tensional|NN system|NN .|. 

Terraces|NNP The|DT vertical|JJ warping|VBG of|IN terraces|NNS ,|, as|IN a|DT result|NN of|IN deformation|NN ,|, has|VBZ been|VBN studied|VBN by|IN numerous|JJ investigators|NNS (|( Machida|NNP ,|, 1960|CD ;|: Zuchiewicz|NNP ,|, 1980|CD ;|: King|NNP and|CC Stein|NNP ,|, 1983|CD )|) .|. 
The|DT offset|VBN of|IN terraces|NNS by|IN lateral|NN faulting|VBG gives|VBZ a|DT clear|JJ indication|NN of|IN fault|NN movement|NN .|. 
The|DT offset|VBN terraces|NNS at|IN the|DT mouth|NN of|IN the|DT Waiohine|NNP Gorge|NNP in|IN New|NNP Zealand|NNP shows|VBZ the|DT amount|NN of|IN displacement|NN and|CC the|DT episodic|JJ nature|NN of|IN the|DT displacement|NN (|( Figure|NN 2.12|CD )|) .|. 
In|IN addition|NN to|TO river|NN terraces|NNS ,|, the|DT deformation|NN of|IN lake|NN terraces|NNS and|CC marine|JJ terraces|NNS (|( Keller|NNP and|CC Pinter|NNP ,|, 1996|CD )|) are|VBP proof|NN of|IN isostatic|JJ and|CC tectonic|JJ activity|NN because|IN they|PRP formed|VBD horizontally|RB at|IN a|DT given|VBN water|NN level|NN .|. 
An|DT example|NN is|VBZ the|DT isostatic|JJ deformation|NN of|IN the|DT Pleistocene|NNP Lake|NNP Bonneville|NNP shorelines|NNS ,|, Utah|NNP (|( Crittenden|NNP ,|, 1963|CD )|) .|. 
Portions|NNP of|IN the|DT Lake|NNP Bonneville|NNP shorelines|NNS have|VBP been|VBN deformed|VBN as|RB much|JJ as|IN 210|CD feet|NNS ,|, as|IN it|PRP drained|VBN and|CC evaporated|VBN to|TO form|VB Great|NNP Salt|NNP Lake|NNP .|. 
In|IN addition|NN ,|, deformed|VBN marine|JJ terraces|NNS provide|VBP an|DT excellent|JJ indication|NN of|IN recent|JJ deformation|NN along|IN 440|CD km|NN of|IN the|DT Pacific|NNP Coast|NNP of|IN Baja|NNP ,|, California|NNP (|( Orme|NNP ,|, 1980|CD )|) .|. 
Not|RB only|RB are|VBP terraces|NNS deformed|VBN ,|, but|CC as|IN an|DT uplift|NN is|VBZ crossed|VBN ,|, a|DT floodplain|NN can|MD be|VB converted|VBN to|TO a|DT low|JJ terrace|NN .|. 
This|DT will|MD ,|, of|IN course|NN ,|, dramatically|RB alter|VB the|DT hydraulics|NNS and|CC hydrology|NN of|IN the|DT reach|NN .|. 

In|IN addition|NN to|TO the|DT obvious|JJ evidence|NN of|IN deformation|NN described|VBD above|IN ,|, evidence|NN of|IN deformation|NN is|VBZ provided|VBN by|IN alluvial|JJ deposits|NNS and|CC paleosoils|NNS (|( Machette|NNP ,|, 1978|CD ;|: Keller|NNP et|CC al.|NN ,|, 1982|CD ;|: Bull|NNP ,|, 1984|CD ;|: Rockwell|NNP et|CC al.|NN ,|, 1984|CD ;|: Rockwell|NNP ,|, 1988|CD )|) by|IN variations|NNS in|IN gradients|NNS of|IN streams|NNS of|IN different|JJ orders|NNS (|( Merritts|NNP and|CC Vincent|NNP ,|, 1989|CD ;|: Merritts|NNP and|CC Hesterberg|NNP ,|, 1994|CD )|) and|CC by|IN variations|NNS of|IN valley|NN and|CC river|NN longitudinal|NN profiles|NNS (|( Volkov|NNP et|CC al.|NN ,|, 1967|CD ;|: Seeber|NNP and|CC Gornitz|NNP ,|, 1983|CD )|) .|. 

NULL|NNP 
Figure|NN 2.12|CD Block|NNP diagram|NN of|IN the|DT displaced|VBN river|NN terraces|NNS at|IN the|DT mouth|NN of|IN the|DT Waiohine|NNP Gorge|NNP ,|, New|NNP Zealand|NNP .|. The|DT West|NNP Wairarapa|NNP Fault|NNP extends|VBZ from|IN bottom|NN left|VBD (|( southwest|JJS )|) to|TO top|VB right|NN (|( northeast|RB )|) and|CC has|VBZ cut|VBN and|CC moved|VBD successive|JJ river|NN terraces|NNS (|( I|NN =|SYM oldest|JJS terrace|NN ;|: VI|NNP =|SYM youngest|JJS terrace|NN )|) .|. 
The|DT amount|NN (|( in|IN feet|NNS )|) each|DT terrace|NN has|VBZ been|VBN moved|VBN by|IN the|DT fault|NN is|VBZ indicated|VBN (|( H|NNP =|SYM amount|NN of|IN horizontal|NN movement|NN ;|: V|NNP =|SYM amount|NN of|IN vertical|JJ movement|NN )|) .|. 
The|DT length|NN of|IN the|DT fault|NN shown|VBN on|IN the|DT diagram|NN is|VBZ about|IN 0.8|CD km|NN (|( 1/2|CD mile|NN )|) (|( modified|VBN after|IN Stevens|NNP ,|, 1974|CD )|) .|. 

River|NN response|NN The|DT clearest|NN evidence|NN for|IN tectonic|JJ effects|NNS on|IN rivers|NNS are|VBP anomalous|JJ reaches|NNS that|DT show|NN dramatic|JJ changes|NNS of|IN pattern|NN trend|NN and|CC gradient|NN that|DT cannot|NN be|VB attributed|VBN to|TO other|JJ causes|NNS .|. 
Structural|JJ geologists|NNS and|CC petroleum|NN geologists|NNS have|VBP known|VBN for|IN years|NNS that|IN rivers|NNS are|VBP strong|JJ indicators|NNS of|IN faulting|VBG (|( Lattman|NNP ,|, 1959|CD ;|: Howard|NNP ,|, 1967|CD )|) .|. 

Tectonic|NNP activity|NN can|MD significantly|RB control|VB river|NN patterns|NNS and|CC behavior|NN ,|, and|CC this|DT is|VBZ especially|RB true|JJ of|IN alluvial|JJ rivers|NNS .|. 
Neef|NNP (|( 1966|CD )|) and|CC Radulescu|NNP (|( 1962|CD )|) state|NN that|IN neotectonic|JJ movements|NNS can|MD be|VB reflected|VBN only|RB in|IN those|DT geomorphic|JJ features|NNS that|WDT react|VBP to|TO the|DT smallest|JJS changes|NNS of|IN slope|NN ,|, such|JJ as|IN meander|NN characteristics|NNS .|. 
In|IN addition|NN ,|, the|DT variations|NNS of|IN thickness|NN and|CC distribution|NN of|IN recent|JJ sediments|NNS indicate|VBP the|DT variability|NN of|IN tectonics|NNS in|IN a|DT given|VBN valley|NN .|. 
Clearly|RB ,|, one|CD of|IN the|DT most|RBS sensitive|JJ indicators|NNS of|IN change|NN is|VBZ the|DT valley|NN floor|NN profile|NN and|CC longitudinal|NN profile|NN of|IN a|DT stream|NN (|( Bendefy|NNP et|CC al.|NN ,|, 1967|CD ;|: Zuchiewicz|NNP ,|, 1979|CD )|) .|. 

Alluvial|NNP rivers|NNS will|MD be|VB very|RB sensitive|JJ indicators|NNS of|IN valley|NN slope|NN change|NN .|. 
In|IN order|NN to|TO maintain|VB a|DT constant|JJ gradient|NN ,|, a|DT river|NN that|WDT is|VBZ being|VBG steepened|JJ by|IN a|DT downstream|JJ tilt|NN will|MD increase|VB its|PRP$ sinuosity|NN or|CC braid|NN ,|, whereas|IN a|DT reduction|NN of|IN valley|NN slope|NN will|MD lead|VB to|TO a|DT reduction|NN of|IN sinuosity|NN or|CC aggradation|NN if|IN the|DT pattern|NN cannot|NN change|NN .|. 
For|IN example|NN ,|, Twidale|NNP (|( 1966|CD )|) reported|VBD that|IN both|DT the|DT Flinders|NNP and|CC Leichardt|NNP Rivers|NNP have|VBP changed|VBN to|TO a|DT braided|JJ pattern|NN ,|, as|IN a|DT result|NN of|IN the|DT steepening|VBG of|IN their|PRP$ gradient|NN by|IN the|DT Selwyn|NNP Upwarp|NNP in|IN northern|JJ Queensland|NNP ,|, Australia|NNP ;|: and|CC the|DT Red|NNP River|NNP near|IN Winnipeg|NNP ,|, Canada|NNP is|VBZ straightening|VBG ,|, as|IN a|DT result|NN of|IN reduction|NN of|IN gradient|NN by|IN isostatic|JJ rebound|NN (|( Welch|NNP ,|, 1973|CD )|) .|. 
Other|JJ examples|NNS are|VBP provided|VBN by|IN the|DT Mississippi|NNP River|NNP between|IN St.|NN Louis|NNP and|CC Cairo|NNP and|CC the|DT lower|JJR Missouri|NNP River|NNP (|( Adams|NNP ,|, 1980|CD )|) as|RB well|RB as|IN the|DT Red|NNP River|NNP of|IN the|DT North|NNP near|IN Winnipeg|NNP ,|, Canada|NNP (|( Vanicek|NNP and|CC Nagy|NNP ,|, 1980|CD )|) .|. 

Baselevel|NNP changes|NNS can|MD also|RB resemble|VB the|DT effects|NNS of|IN active|JJ tectonics|NNS ,|, and|CC can|MD provide|VB information|NN on|IN channel|NN change|NN .|. 
For|IN example|NN ,|, if|IN sea|NN -|- level|NN is|VBZ lowered|VBN ,|, and|CC a|DT steep|JJ portion|NN of|IN the|DT continental|JJ shelf|NN is|VBZ exposed|VBN ,|, the|DT effect|NN will|MD be|VB like|IN that|DT downstream|JJ of|IN the|DT axis|NNS of|IN an|DT uplift|NN .|. 
Lane|NNP (|( 1955|CD )|) argued|VBD that|IN a|DT lowering|VBG of|IN baselevel|NN will|MD cause|VB channel|NN adjustment|NN throughout|IN most|JJS of|IN the|DT river|NN .|. 
Indeed|RB ,|, Lane|NNP ’|NN s|VBZ (|( 1955|CD )|) argument|NN that|IN a|DT stream|NN will|MD restore|VB its|PRP$ gradient|NN at|IN a|DT higher|JJR or|CC lower|JJR level|NN following|VBG a|DT baselevel|NN change|NN is|VBZ conceptually|RB correct|JJ because|IN if|IN the|DT river|NN is|VBZ initially|RB at|IN grade|NN ,|, then|RB to|TO move|VB its|PRP$ sediment|NN load|NN and|CC water|NN discharge|NN through|IN the|DT channel|NN ,|, the|DT original|JJ gradient|NN of|IN the|DT stream|NN must|MD be|VB reestablished|JJ .|. 
However|RB ,|, sediment|NN loads|NNS may|MD be|VB greater|JJR after|IN channel|NN incision|NN and|CC less|JJR after|IN aggradation|NN .|. 
Another|DT fallacy|NN in|IN Lane|NNP ’|NN s|VBZ argument|NN is|VBZ the|DT assumption|NN that|IN the|DT valley|NN slope|NN and|CC channel|NN gradient|NN are|VBP identical|JJ .|. 
This|DT is|VBZ not|RB the|DT case|NN ,|, and|CC the|DT two|CD -|- dimensional|JJ perspective|NN leads|VBZ to|TO erroneous|JJ conclusions|NNS .|. 
For|IN example|NN ,|, a|DT sinuous|JJ river|NN has|VBZ a|DT gradient|NN less|JJR than|IN that|DT of|IN the|DT valley|NN floor|NN .|. 

Sinuosity|NNP (|( P|NN )|) is|VBZ the|DT ratio|NN between|IN channel|NN length|NN (|( L|NNP c|SYM )|) and|CC valley|NN length|NN (|( L|NNP v|NN )|) ,|, and|CC it|PRP is|VBZ also|RB the|DT ratio|NN between|IN valley|NN slope|NN (|( S|NNP v|NN )|) and|CC channel|NN gradient|NN (|( S|NNP c|SYM )|) as|IN follows|VBZ :|: 

Therefore|RB ,|, a|DT straight|JJ channel|NN has|VBZ a|DT sinuosity|NN of|IN 1.0|CD ,|, and|CC the|DT gradient|NN of|IN the|DT channel|NN and|CC the|DT slope|NN of|IN the|DT valley|NN floor|NN are|VBP the|DT same|JJ .|. 
It|PRP has|VBZ been|VBN demonstrated|VBN that|IN rivers|NNS can|MD respond|VB to|TO major|JJ changes|NNS of|IN water|NN and|CC sediment|NN load|NN primarily|RB by|IN pattern|NN changes|NNS (|( Schumm|NNP ,|, 1968|CD )|) ,|, and|CC that|IN much|JJ of|IN the|DT pattern|NN variability|NN of|IN large|JJ alluvial|JJ rivers|NNS such|JJ as|IN the|DT Mississippi|NNP ,|, Indus|NNP ,|, and|CC Nile|NNP ,|, reflect|VBP the|DT variability|NN of|IN the|DT valley|NN slope|NN (|( Schumm|NNP et|CC al.|NN ,|, 1994|CD ;|: Jorgensen|NNP et|CC al.|NN ,|, 1993|CD ;|: Schumm|NNP and|CC Galay|NNP ,|, 1994|CD )|) .|. 

NULL|NNP 
Figure|NN 2.13|CD Effect|NN of|IN a|DT baselevel|NN fall|NN on|IN channel|NN length|NN and|CC pattern|NN .|. See|VB text|NN for|IN discussion|NN .|. 

Figure|NN 2.13|CD illustrates|VBZ this|DT concept|NN geometrically|RB ,|, and|CC it|PRP shows|VBZ the|DT impact|NN of|IN the|DT lowering|VBG of|IN baselevel|NN in|IN a|DT valley|NN with|IN a|DT stream|NN of|IN sinuosity|NN (|( P|NN )|) 1.5|CD .|. 
The|DT line|NN A–C|NNP represents|VBZ the|DT channel|NN profile|NN ,|, and|CC the|DT line|NN A–B|NNP represents|VBZ the|DT profile|NN of|IN the|DT valley|NN floor|NN .|. 
Points|NNPS B|NNP and|CC C|NNP are|VBP at|IN the|DT river|NN mouth|NN ,|, and|CC points|NNS F|NN and|CC G|NNP are|VBP at|IN the|DT same|JJ location|NN in|IN the|DT valley|NN .|. 
The|DT channel|NN distance|NN is|VBZ one|CD -|- third|JJ longer|RBR than|IN the|DT valley|NN distance|NN ,|, and|CC the|DT difference|NN in|IN channel|NN and|CC valley|NN slope|NN reflects|VBZ the|DT sinuosity|NN of|IN the|DT stream|NN .|. 
The|DT length|NN of|IN the|DT channel|NN is|VBZ 1.5|CD times|NNS the|DT length|NN of|IN the|DT valley|NN and|CC ,|, therefore|RB ,|, the|DT stream|NN gradient|NN is|VBZ one|CD -|- third|JJ less|JJR than|IN the|DT valley|NN slope|NN (|( equation|NN 1|CD )|) .|. 
If|IN a|DT vertical|JJ fall|NN of|IN baselevel|NN from|IN B|NNP to|TO D|NNP and|CC C|NNP to|TO E|NNP is|VBZ assumed|VBN ,|, channel|NN incision|NN and|CC lateral|NN erosion|NN will|MD steepen|NN the|DT valley|NN floor|NN .|. 
If|IN the|DT channel|NN is|VBZ not|RB confined|VBN laterally|RB ,|, it|PRP can|MD adjust|VB to|TO the|DT increased|VBN valley|NN slope|NN (|( F–D|NNP )|) by|IN increasing|VBG sinuosity|NN to|TO 2.0|CD ,|, and|CC the|DT channel|NN profile|NN is|VBZ extended|VBN to|TO H.|NN 
In|IN this|DT case|NN ,|, incision|NN ceases|VBZ at|IN point|NN F|NN in|IN the|DT valley|NN and|CC at|IN point|NN G|NNP in|IN the|DT channel|NN because|IN the|DT increase|NN of|IN sinuosity|NN from|IN 1.5|CD to|TO 2.0|CD from|IN G|NNP to|TO H|NNP maintains|VBZ a|DT constant|JJ channel|NN gradient|NN over|IN the|DT reach|NN of|IN increased|VBN valley|NN slope|NN (|( F|NNP –|- D|NNP )|) .|. 
The|DT one|CD -|- third|JJ increase|NN of|IN channel|NN length|NN (|( sinuosity|NN )|) between|IN G|NNP and|CC H|NNP compensates|VBZ for|IN a|DT one|CD -|- third|JJ steepening|VBG of|IN the|DT valley|NN floor|NN from|IN F|NN to|TO D.|NN 

According|VBG to|TO Lane|NNP ’|NN s|VBZ assumptions|NNS ,|, the|DT effect|NN of|IN this|DT baselevel|NN fall|NN would|MD be|VB propagated|JJ upstream|RB to|TO point|VB A|DT ,|, where|WRB an|DT amount|NN of|IN erosion|NN equal|JJ to|TO B–D|NNP would|MD occur|VB .|. 
However|RB ,|, because|IN the|DT stream|NN can|MD adjust|VB ,|, the|DT steepening|VBG of|IN the|DT valley|NN floor|NN will|MD not|RB result|VB in|IN a|DT change|NN of|IN stream|NN gradient|NN .|. 
Rather|RB the|DT channel|NN lengthens|VBZ ,|, and|CC the|DT effect|NN of|IN baselevel|NN lowering|VBG is|VBZ propagated|JJ only|RB a|DT relatively|RB short|JJ distance|NN upstream|RB .|. 
The|DT distance|NN will|MD undoubtedly|RB depend|VB on|IN local|JJ conditions|NNS and|CC the|DT original|JJ slope|NN of|IN the|DT valley|NN floor|NN ,|, but|CC this|DT exercise|NN supports|VBZ Saucier|NNP ’|NN s|VBZ (|( 1991|CD )|) contention|NN that|IN Pleistocene|NNP sea|NN level|NN change|NN in|IN the|DT lower|JJR Mississippi|NNP valley|NN was|VBD effective|JJ only|RB as|RB far|RB as|IN Baton|NNP Rouge|NNP (|( see|VB also|RB Blum|NNP ,|, 1993|CD and|CC Blum|NNP and|CC Valastro|NNP ,|, 1994|CD )|) .|. 
The|DT probability|NN that|IN a|DT large|JJ river|NN can|MD adjust|VB in|IN this|DT fashion|NN is|VBZ made|VBN more|RBR likely|JJ by|IN the|DT fact|NN that|IN the|DT baselevel|NN changes|NNS in|IN nature|NN will|MD take|VB place|NN relatively|RB slowly|RB and|CC not|RB abruptly|RB ,|, unlike|IN during|IN the|DT experimental|JJ studies|NNS .|. 
The|DT river|NN ,|, therefore|RB ,|, has|VBZ more|JJR time|NN to|TO adjust|VB by|IN changing|VBG sinuosity|NN .|. 

Further|RB evidence|NN for|IN the|DT type|NN of|IN channel|NN response|NN shown|VBN in|IN Figure|NN 2.13|CD is|VBZ demonstrated|VBN by|IN the|DT experimental|JJ studies|NNS of|IN Jeff|NNP Ware|NNP (|( 1992|CD oral|JJ comm|NN .|. )|) .|. 
He|PRP lowered|VBD baselevel|NN relatively|RB slowly|RB to|TO a|DT maximum|NN of|IN 12|CD cm|NN in|IN a|DT flume|NN with|IN a|DT total|JJ length|NN of|IN 18.4|CD m|NN .|. 
This|DT change|NN would|MD have|VB doubled|VBN the|DT channel|NN gradient|NN .|. 
However|RB ,|, the|DT effect|NN of|IN the|DT baselevel|NN lowering|VBG extended|VBN only|RB 4|CD m|NN upstream|RB ,|, and|CC the|DT change|NN in|IN baselevel|NN was|VBD accommodated|VBN by|IN an|DT increase|NN of|IN sinuosity|NN from|IN 1.2|CD to|TO 1.5|CD in|IN the|DT lower|JJR 4|CD m|NN in|IN the|DT flume|NN .|. 
It|PRP is|VBZ clear|JJ ,|, however|RB ,|, that|DT pattern|NN change|NN did|VBD not|RB totally|RB compensate|VB for|IN the|DT change|NN of|IN baselevel|NN .|. 
This|DT channel|NN widened|VBD and|CC roughness|NNS increased|VBN ,|, thereby|RB assuming|VBG part|NN of|IN the|DT adjustment|NN to|TO the|DT baselevel|NN change|NN .|. 

Ware|NNP ’|NN s|VBZ experiments|NNS showed|VBN that|IN a|DT sinuosity|NN increase|NN ,|, which|WDT resulted|VBD in|IN a|DT slope|NN decrease|NN ,|, was|VBD only|RB part|NN of|IN the|DT adjustment|NN ,|, and|CC width|NN ,|, depth|NN ,|, and|CC roughness|NNS adjusted|VBN to|TO decrease|VB velocity|NN and|CC stream|NN power|NN .|. 
Therefore|RB ,|, channel|NN pattern|NN change|NN may|MD only|RB absorb|VB part|NN of|IN a|DT valley|NN slope|NN or|CC baselevel|NN change|NN .|. 
The|DT River|NNP Nile|NNP provides|VBZ an|DT example|NN of|IN such|JJ shared|VBN adjustment|NN with|IN both|DT sinuosity|NN and|CC width|NN changing|VBG as|IN valley|NN slope|NN changes|NNS (|( Schumm|NNP and|CC Galay|NNP ,|, 1994|CD )|) .|. 

Changes|NNS of|IN valley|NN -|- floor|NN gradient|NN provide|VBP an|DT explanation|NN of|IN downstream|JJ pattern|NN variations|NNS ,|, but|CC variations|NNS of|IN valley|NN -|- floor|NN slope|NN can|MD be|VB the|DT result|NN of|IN several|JJ influences|NNS .|. 
Tectonic|NNP activity|NN may|MD change|VB the|DT slope|NN of|IN the|DT valley|NN floor|NN and|CC have|VBP its|PRP$ effect|NN on|IN the|DT channel|NN pattern|NN (|( Adams|NNP ,|, 1980|CD )|) .|. 
In|IN addition|NN ,|, a|DT high|JJ -|- sediment|NN -|- transporting|JJ tributary|JJ may|MD build|VB a|DT fan|NN -|- like|IN deposit|NN in|IN the|DT valley|NN ,|, which|WDT will|MD persist|VB even|RB after|IN the|DT tributary|JJ sediment|NN load|NN has|VBZ decreased|VBN .|. 
When|WRB the|DT main|JJ river|NN crosses|VBZ this|DT fan|NN ,|, pattern|NN changes|NNS will|MD result|VB ,|, as|IN the|DT river|NN attempts|NNS to|TO maintain|VB a|DT constant|JJ gradient|NN .|. 
Tributaries|NNP to|TO the|DT Jordan|NNP River|NNP in|IN Israel|NNP have|VBP developed|VBN fan|NN -|- like|IN deposits|NNS in|IN the|DT valley|NN ,|, and|CC the|DT valley|NN floor|NN of|IN the|DT Jordan|NNP Valley|NNP undulates|NNS as|IN a|DT result|NN .|. 
The|DT Jordan|NNP River|NNP ,|, as|IN it|PRP approaches|VBZ one|CD of|IN these|DT convexities|NNS ,|, straightens|NNS as|IN it|PRP crosses|VBZ the|DT upstream|JJ flatter|NN part|NN of|IN the|DT fan|NN and|CC then|RB it|PRP develops|VBZ a|DT more|RBR sinuous|JJ course|NN on|IN the|DT steeper|JJR downstream|JJ side|NN of|IN the|DT fan|NN (|( Schumm|NNP ,|, 1977|CD ,|, p.|NN 140|CD )|) .|. 

It|PRP is|VBZ important|JJ to|TO realize|VB that|IN channels|NNS that|WDT lie|VBP near|IN a|DT pattern|NN threshold|NN (|( Figure|NN 2.3|CD )|) may|MD change|VB their|PRP$ characteristics|NNS dramatically|RB with|IN only|RB a|DT slight|JJ change|NN in|IN the|DT controlling|VBG variable|JJ .|. 
For|IN example|NN ,|, some|DT rivers|NNS that|WDT are|VBP meandering|VBG and|CC that|WDT are|VBP near|IN pattern|NN thresholds|NNS become|VBP braided|JJ with|IN only|RB a|DT small|JJ addition|NN of|IN bed|NN load|NN (|( Schumm|NNP ,|, 1979|CD )|) .|. 
Experimental|NNP studies|NNS and|CC field|NN observations|NNS confirm|VBP that|IN a|DT change|NN of|IN valley|NN -|- floor|NN slope|NN will|MD cause|VB a|DT change|NN of|IN channel|NN morphology|NN .|. 
The|DT change|NN will|MD differ|VB ,|, however|RB ,|, depending|VBG where|WRB the|DT channel|NN lies|VBZ on|IN a|DT plot|NN such|JJ as|IN that|DT of|IN Figure|NN 2.3|CD and|CC depending|VBG on|IN the|DT type|NN of|IN channel|NN (|( Figure|NN 2.4|CD )|) .|. 
For|IN example|NN ,|, with|IN increasing|VBG slope|NN ,|, a|DT straight|JJ channel|NN will|MD become|VB sinuous|JJ ,|, a|DT low|JJ sinuosity|NN channel|NN will|MD become|VB more|RBR sinuous|JJ ,|, and|CC a|DT meandering|VBG channel|NN will|MD braid|NN .|. 
With|IN decreasing|VBG slope|NN ,|, a|DT braided|JJ channel|NN will|MD meander|NN and|CC a|DT meandering|VBG channel|NN will|MD straighten|VB .|. 

NULL|NNP 
Figure|NN 2.14|CD Reaches|NNP of|IN degradation|NN and|CC aggradation|NN associated|VBN with|IN uplift|NN and|CC faulting|VBG .|. 
Although|IN pattern|NN changes|NNS may|MD dominate|VB river|NN response|NN ,|, deposition|NN in|IN reaches|NNS of|IN reduced|VBN gradient|NN is|VBZ likely|JJ as|IN is|VBZ channel|NN incision|NN and|CC bank|NN erosion|NN in|IN reaches|NNS of|IN steepened|JJ gradient|NN (|( Figure|NN 2.14|CD )|) .|. 
In|IN fact|NN ,|, upstream|RB deposition|NN will|MD reduce|VB downstream|JJ sediment|NN loads|NNS thereby|RB increasing|VBG the|DT tendency|NN for|IN downstream|JJ erosion|NN .|. 
Therefore|RB ,|, in|IN addition|NN to|TO the|DT primary|JJ valley|NN -|- floor|NN deformation|NN by|IN active|JJ tectonics|NNS and|CC the|DT secondary|JJ channel|NN response|NN to|TO this|DT deformation|NN ,|, there|EX are|VBP third|JJ -|- order|NN effects|NNS beyond|IN the|DT area|NN of|IN deformation|NN .|. 
For|IN example|NN ,|, deposition|NN upstream|RB from|IN the|DT axis|NNS of|IN a|DT dome|NN can|MD progress|VB further|JJ upstream|RB by|IN backfilling|VBG beyond|IN the|DT area|NN of|IN active|JJ deformation|NN (|( Figure|NN 2.14|CD )|) .|. 
This|DT means|VBZ that|IN the|DT uplift|NN is|VBZ acting|VBG as|IN a|DT dam|NN ,|, and|CC unless|IN erosion|NN on|IN the|DT steeper|JJR downstream|JJ side|NN of|IN the|DT uplift|NN produces|VBZ sufficient|JJ sediment|NN to|TO compensate|VB ,|, erosion|NN will|MD occur|VB downstream|JJ beyond|IN the|DT limits|NNS of|IN deformation|NN .|. 
However|RB ,|, it|PRP is|VBZ more|RBR likely|JJ that|WDT reduced|VBD sediment|NN load|NN will|MD accelerate|VB erosion|NN on|IN the|DT steeper|JJR downstream|JJ reach|NN ,|, and|CC when|WRB this|DT increased|JJ load|NN moves|NNS downstream|JJ ,|, aggradation|NN will|MD result|VB (|( Figure|NN 2.14|CD )|) .|. 

NULL|NNP 
Figure|NN 2.15|CD Effect|NN of|IN change|NN from|IN weaker|JJR (|( W|NNP )|) to|TO more|RBR resistant|JJ (|( R|NN )|) materials|NNS on|IN meander|NN pattern|NN .|. 
Another|DT aspect|NN of|IN both|DT active|JJ and|CC neotectonics|NNS is|VBZ the|DT appearance|NN of|IN more|JJR resistant|JJ materials|NNS in|IN the|DT channel|NN as|IN the|DT channel|NN degrades|NNS .|. 
Resistant|NNP alluvium|NN (|( clay|NN plugs|NNS ,|, gravel|NN armor|NN )|) or|CC bedrock|NN will|MD confine|NN the|DT channel|NN and|CC retard|VB meander|NN shift|NN and|CC bank|NN erosion|NN .|. 
The|DT result|NN should|MD be|VB deformed|VBN or|CC compressed|VBN meanders|VBZ upstream|RB and|CC a|DT change|NN of|IN meander|NN character|NN at|IN the|DT contact|NN .|. 
For|IN example|NN ,|, as|IN meanders|VBZ shift|NN downvalley|NN ,|, their|PRP$ movement|NN may|MD be|VB retarded|JJ if|IN more|RBR resistant|JJ alluvium|NN or|CC bedrock|NN is|VBZ encountered|VBN (|( Jin|NNP and|CC Schumm|NNP ,|, 1987|CD )|) .|. 
Hence|RB ,|, a|DT fault|NN may|MD present|VB a|DT barrier|NN with|IN the|DT result|NN that|WDT upstream|RB meanders|VBZ are|VBP compressed|VBN and|CC deformed|VBN (|( Figure|NN 2.15|CD )|) .|. 
A|DT similar|JJ pattern|NN will|MD result|VB if|IN the|DT river|NN encounters|VBZ bedrock|NN as|IN it|PRP crosses|VBZ an|DT upwarp|NN or|CC if|IN ,|, as|IN a|DT result|NN of|IN incision|NN ,|, it|PRP encounters|VBZ resistant|JJ materials|NNS in|IN a|DT portion|NN of|IN its|PRP$ course|NN .|. 
Yeromenko|NNP and|CC Ivanov|NNP (|( 1977|CD )|) reviewed|VBD the|DT Russian|JJ literature|NN and|CC concluded|VBD that|IN for|IN rivers|NNS crossing|VBG uplifts|NNS ,|, the|DT largest|JJS number|NN of|IN meanders|VBZ occur|VB upstream|RB of|IN the|DT structures|NNS ,|, which|WDT supports|VBZ Gardner|NNP ’|NN s|VBZ (|( 1975|CD )|) observations|NNS of|IN bedrock|NN channels|NNS in|IN the|DT Colorado|NNP Plateau|NNP .|. 
This|DT is|VBZ the|DT reverse|NN of|IN what|WP is|VBZ expected|VBN for|IN alluvial|JJ channels|NNS from|IN the|DT relation|NN of|IN Figure|NN 2.3|CD .|. 
Therefore|RB ,|, an|DT investigator|NN must|MD not|RB simply|RB base|VB conclusions|NNS on|IN river|NN pattern|NN alone|RB .|. 

Discussion|NNP Alluvium|NNP is|VBZ usually|RB assumed|VBN to|TO hide|VB the|DT underlying|VBG geology|NN ,|, but|CC rates|NNS of|IN active|JJ tectonic|JJ movement|NN are|VBP sufficiently|RB rapid|JJ to|TO affect|VB the|DT morphology|NN and|CC behavior|NN of|IN alluvial|JJ rivers|NNS .|. 
Rivers|NNP being|VBG the|DT most|RBS sensitive|JJ components|NNS of|IN the|DT landscape|NN will|MD provide|VB evidence|NN of|IN even|RB ,|, slow|JJ ,|, aseismic|JJ tectonic|JJ activity|NN .|. 
For|IN example|NN ,|, evidence|NN of|IN active|JJ tectonics|NNS is|VBZ as|IN follows|VBZ :|: 

1|CD 
.|. deformation|NN of|IN valley|NN floor|NN longitudinal|NN profile|NN 2|CD .|. deformation|NN of|IN channel|NN longitudinal|NN profile|NN 3|CD .|. change|NN of|IN channel|NN pattern|NN 4|CD .|. change|NN of|IN channel|NN width|NN and|CC depth|NN 5|CD .|. conversion|NN of|IN floodplain|NN to|TO a|DT low|JJ terrace|NN 6|CD .|. reaches|NNS of|IN active|JJ channel|NN incision|NN or|CC lateral|NN shift|NN 7|CD .|. effects|NNS both|DT upstream|RB and|CC downstream|JJ of|IN the|DT zone|NN of|IN deformation|NN (|( degradation|NN ,|, aggradation|NN ,|, flooding|NN ,|, bank|NN erosion|NN )|) 8|CD .|. formation|NN of|IN lakes|NNS 
Alluvial|NNP channels|NNS are|VBP sensitive|JJ indicators|NNS of|IN change|NN ,|, but|CC they|PRP also|RB adjust|VBP to|TO changes|NNS of|IN hydrology|NN and|CC sediment|NN load|NN as|RB well|RB as|IN to|TO active|JJ tectonics|NNS .|. 
Therefore|RB ,|, it|PRP may|MD be|VB difficult|JJ to|TO determine|VB the|DT cause|NN of|IN channel|NN change|NN when|WRB ,|, in|IN fact|NN ,|, human|JJ activities|NNS have|VBP been|VBN changing|VBG both|DT discharge|NN and|CC sediment|NN load|NN during|IN historic|JJ time|NN .|. 
Pattern|NNP change|NN alone|RB is|VBZ not|RB sufficient|JJ evidence|NN for|IN active|JJ tectonics|NNS ,|, rather|RB it|PRP is|VBZ one|CD bit|NN of|IN evidence|NN that|WDT must|MD be|VB supported|VBN with|IN other|JJ morphologic|JJ evidence|NN and|CC /|NN or|CC surveys|NNS that|WDT provide|VBP clear|JJ evidence|NN of|IN deformation|NN .|. 
In|IN many|JJ areas|NNS ,|, the|DT evidence|NN will|MD be|VB circumstantial|JJ .|. 
Nevertheless|RB ,|, anomalous|JJ reaches|NNS that|WDT are|VBP not|RB related|VBN to|TO artificial|JJ controls|NNS ,|, tributary|JJ influences|NNS ,|, lithologic|JJ change|NN ,|, or|CC paleotectonics|NNS may|MD reasonably|RB be|VB assumed|VBN to|TO be|VB the|DT result|NN of|IN active|JJ tectonics|NNS until|IN proved|VBD otherwise|RB .|. 

Lakes|NNP can|MD also|RB provide|VB information|NN on|IN subsidence|NN ,|, and|CC ria|NN lakes|NNS can|MD be|VB evidence|NN of|IN tilting|VBG or|CC even|RB hydrologic|JJ and|CC climatic|JJ influences|NNS .|. 
For|IN example|NN ,|, during|IN Pleistocene|NNP aggradation|NN in|IN the|DT Ohio|NNP River|NNP and|CC Mississippi|NNP River|NNP valleys|NNS ,|, numerous|JJ lakes|NNS formed|VBN in|IN tributary|JJ valleys|NNS .|. 
Therefore|RB ,|, care|NN must|MD be|VB exercised|VBN when|WRB determining|VBG the|DT tectonic|JJ significance|NN of|IN lakes|NNS and|CC other|JJ river|NN anomalies|NNS .|. 

