Planning With Contours

AIM

AIM

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• To understTo understand the various concerns while plannand the various concerns while planning with contours.ing with contours.

LIMITATIONs

LIMITATIONs

•

• Calculation part is not discussed.Calculation part is not discussed.

INTRODUCTION

INTRODUCTION

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• An imaginar line that connects all points o! e"ual elevation a#ove or #elow a !i$ed re!erence plane orAn imaginar line that connects all points o! e"ual elevation a#ove or #elow a !i$ed re!erence plane or

datum. datum.

•

• In other words% contour is a line in In other words% contour is a line in which the groundwhich the ground sur!ace is intersected # a level sur!ace o#tained #sur!ace is intersected # a level sur!ace o#tained #

 &oining points o! e"ual elevation.  &oining points o! e"ual elevation.

•

• Contour line is a graphic representation o! a contour on a plan or map.Contour line is a graphic representation o! a contour on a plan or map.

•

• The process o! tracing contour lines on The process o! tracing contour lines on the sur!ace o! earth is called contouringthe sur!ace o! earth is called contouring

..

T'RMINOLO()

T'RMINOLO()

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• *teep slopes + Contours are closel spaced.*teep slopes + Contours are closel spaced.

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• (entle slopes + Contours are less closel spaced .(entle slopes + Contours are less closel spaced .

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• ,ori-ontal '"uivalent  ,ori-ontal '"uivalent  The hori-ontal distance #etween two The hori-ontal distance #etween two consecutive contour lines .consecutive contour lines .

•

• Contour Interval +The constant vertical distance #etween two consecutive contours is called the contourContour Interval +The constant vertical distance #etween two consecutive contours is called the contour

interval. interval.

•

• Mean *ea Level + Average height o! the sur!ace o! sea !or all stages o! the tide.Mean *ea Level + Average height o! the sur!ace o! sea !or all stages o! the tide.

•

• 'levations + /e'levations + /ertical distance !rom the rtical distance !rom the datum to the datum to the plane.plane.

•

• ,ILL

• A hill is a point or small area o! high ground. 0hen ou are on a hilltop% the ground slopes down in all

directions.

• The height and slope o! a hill are represented on a map # the num#er o! concentric contour rings and

the distance #etween the rings.

• RID('

• A ridge is a line o! high ground with height variations along its crest.

• The contours along the sides o! the ridge will #e relativel parallel and there will #e several high points

along the ridge.

• /ALL')

• A valle is an elongated depression that !orms the space #etween two ridges. • /alle and ridges are interconnected.

• Ridge side slope create the valle walls.

• *ADDL'

• A saddle is a dip or low point along the edge o! a ridge.

• A saddle is not necessaril the lower ground #etween two hilltops. • It ma also #e a #rea1 along an otherwise level ridge .

• D'2R'**ION

• Depression is a low point or hole in the ground that is also surrounded on all sides # higher ground. • Lowest contour at the centre.

CHARACTERISTIC

• All points in a contour line have the same elevation.

•  3lat ground is indicated where the contours are widel separated and steep+slope where the run close

together.

• A series o! closed contour lines on the map represent a hill% i! the higher values are inside.

• A series o! closed contour lines on the map indicate a depression i! the higher values are outside. • 0ater !lows perpendicular to contour lines.

• Contour line cross ridge or valle line at right an gles.

• Contour lines cannot merge or cross one another on map e$cept in the case o! an overhanging cli!!. • Contours cannot end anwhere #ut close on themselves either within or outside the limits o! the map. •  Contour lines never run into one another e$cept in the case o! a vertical cli!!. In this case %several

contours coincide and the hori-ontal e"uivalent #ecomes -ero.

SLOPE ANALYSIS

• It is a analsis o! the steepness o! the terrain.

• To determine the #est areas !or placing #uildings% roads% par1ing lots and other activities on a particular

site.

• Used !or consideration such as economics% vegetation% drainage% soils etc.

• *lopes o! less than a#out 4 percent in the open landscape appear !lat to the human ee. • In order to conduct a slope analsis on a map in!ormation re"uired is+

+ ,ori-ontal scale + Contour interval

+ 2ercentage o! slope categories.

+ *cale and contour interval are esta#lished # the analsis.

GRADING

• (rading is the process o! modi!ication o! e$isting land!orm to accommodate new structures% par1ing and

circulation and to ensure positive drainage.

+ (radient. 6(7

+ ,ori-ontal distance. 6,7

+ Di!!erence in elevation #etween two points. 6D7 ( 8 D9,

(RADIN( /OCA:ULAR)

• Contour Line + A line made up o! points all e"ual in elevation • (radient + The rate o! regular ascent or descent

• *wale + A depressed area o! land used to collect and direct sur!ace water runo!!  • Cross+slope + The latitudinal pitch across an area to increase sur!ace drainage

• 'asement + Land owned # another which entitles the holder to speci!ic limited uses

*IT' (RADIN( T'C,NI;U'*

Anal-e e$isting conditions o! the site5

• (eneral !low o! water 

• '$isting !low lines !or sur!ace runo!!  • '$isting structures% trees% etc. to #e saved

*et preliminar elevations o! structures5

•  Anal-e e$isting elevations o! structures • Chec1 elevations with ad&acent elements

• Chec1 relationships #etween #uildings% wal1s% par1ing lots% etc.

Modi! appropriate contours5

• :egin !rom 1nown points and calculate slope to ne$t contour  • 0or1 each contour line completel to #e sure to meet to e$isting • Calculate re"uired slopes and modi! all other con tours as necessar

(RADIN( M'T,OD*

<. (rading # cutting5

Advantages5 : cutting o!!ers the advantage o! greater soil sta#ilit. It is alread well compacted.

'rosion and setting are minimi-ed.

Disadvantages5 involves disposal e$pence.

Loss o! top soi% reslulting e$posure o! non !ertile soil.

Deep cuts e$pose soil that are not well suited to growing vegetation.

Respreading o! soil over the new sur!ace provides a pro!ile suita#le !or vegetative growth #ut erosion control advantages are lost.

4. (rading # !ill5

This is the method used to raise a low spot when no other method will success!ull drain sur!ace water. Di!!icult to compact large areas to !ill in such a wa that !urther settling will not occur.

Cost e!!ective due to locating% ac"uiring and transporting. =.Com#ining cut and !ill5

Involves #oth cut and !ill in e"ual measure.

It prevents the introduction o! !oreign soils into the area #eing graded and ma1es heav transportation e$penses unnecessar.

 Newl introduced soil causes pro#lems with plant growth. SURFACE DRAINAGE:

• Rules o! drainage are simple% water alwas runs downhill% steeper the hill% the !aster the pace o! the

drainage.

•  0hen we design changing pattern% we create hills 6#unding7 and harmon with surrounding natural

 patterns.

•  Designer tr to minimi-es the erosive e!!ect o! drainage.

•  *ur!ace drainage sstems intercept and collect storm water runo!! and conv e it awa !rom a #uilding

and site with the use o! large inlets and storm drains.

•  *ur!ace and su#sur!ace sstems tpicall re"uire discharge either through a pumping station or #

gravit drainage to an ade"uate out!all.

•  *ur!ace drainage sstems are designed to collect and dispose o! rain!all runo!! to prevent the !low o!

water !rom damaging #uilding structures 6through !oundation lea1age7% site structures% and the sur!ace grade 6through erosion7.

• The shorter the hori-ontal space #etween contours lines% the !aster water will !low.

BUILDING LAYOUT ON CONTOURS

The #uilding should #e placed along the contours to increase the sta#ilit o! the structure and to cut down the cost on the site development.

The e$isting !orm o! the terrain welcomes some #uilding !orms while re&ects some. In hills #uilding #rea1 the continuit o! landscape and hence appear rigid.