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Lab 1: Watershed Delineation ofSanta Clara Catchment

Authors: Anna Le and Yuchong Wang

Submission Date: January, 13 !1"

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Abstract: #he authors used a D$% to &erform 'atershed delineation on the Santa

Clara (i)er Catchment using the tool Arc*+S #hat is, the authors used ele)ation

data from the Santa Clara (i)er region to de-ne a 'atershed.s im&ortant features,including its boundaries, main /o' channels, to&ogra&hic 'etness inde0, and /o'

directions #he to&ogra&hic 'etness inde0 of a small region is de&endent on the

u&stream contributing area as 'ell as the slo&e of the region #he #W+ is also

&ro&ortional to the distance from the surface to the 'ater table y combining our

#W+ ma& 'ith a three2dimensional shading of the region and also com&aring it to an

ele)ation ma&, 'e obser)ed se)eral ey features of the #W+ A large inde0 is

characteristic of &eas, ridges, and hills, 'hile a small inde0 is characteristic of

)alleys #he lo'est #W+ )alues corres&onded to the main stream net'or +n

com&aring the di4erent ma&s generated in the delineation &rocess, it became clear

that #W+, stream net'or, /o' accumulation, /o' direction, slo&e, and ele)ation

are all related to and de&endent on each other and, together, mae u& the bigger

&icture of hydrological beha)ior

+ntroduction: A D$%, or a digital ele)ation model, is a digital grid containing

ele)ation )alues throughout a region A D$% can be used to &redict hydrological

&rocesses +n this re&ort, 'e use a D$% of the Santa Clara (i)er region to de-ne the

ey features of a catchment, including its boundaries, stream net'or, and

to&ogra&hic 'ater inde0 y analy5ing and com&aring the generated ma&s, 'e see

to understand the im&ortance of each feature to the o)erall &icture of hydrology

%ethods:

(esults:

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6igure 1: #his ma& sho's the ele)ation throughout the Santa Clara (i)er Catchment

as 'ell as the delineation of the main stream net'or 7bser)ing these t'o features

together, it is clear that the stream net'or corres&onds to areas 'ith )ery lo'

ele)ation 8see red9 or lo' ele)ation in com&arison to surroundings 8see yello'9

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6igure : #his ma& sho's the to&ogra&hic 'etness indices throughout the Santa

Clara (i)er Catchment y com&aring this ma& to the ele)ation ma& or by looing at

the hill2shading, it is clear that high2ele)ation areas 8mountains9 ha)e lo' #W+ At

-rst glance, it also a&&ears that the higher #W+ )alues 8yello' and blue9 corres&ond

to the main /o' channel We can con-rm this by o)erlaying our delineation of the

stream net'or

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6igure 3: y combining the #W+ ma& 'ith the stream net'or ma&, it is clear that

high #W+ )alues can &redict the stream net'or

Discussion:

Conclusion:

(eferences:

%argulis, S, !1 +ntroduction to ;ydrology, && 3