FLOOD06421

• County: Statewide
• Basin: Statewide
• Title: Highways in the River Environment
• Date: 2/1/1990
• Prepared By: Federal Highway Administration
• Floodplain - Doc Type: Educational/Technical/Reference Information

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Major factms affecting alluvial stream ehann,,[ for illS arto: (I) strt,am
discharge, temperature, \/iscosity; (2) scdimcnt load; 0) lun'Jitudinal slope; (11) ll,mk
and bed resistance to flow; (5) vC'Jctatlon; (6) 'Jeolu'JY, ineludin'; types of scdimcflts;
and en the works of m2rl.
:r he flu'{j"L J:lrocessl~_jnv()I'{cI1 . a[~ .~~_. cUI1l2llca1ed __"ll'UI~'{'3r iahles _'21
jrQflortance art' difficult to isolate. MallY laboratory and field studies have been
carried out in afl attemf't to rclaf_e these and other variables to th" present tin'c_
1 he problem has been more amenable to an empirical solution than an analytical unre.
In an analysis of flow in alluvial rivers, the flow field is complicated by the
constantly changing dischar'Je. Sil]nificant variables are, therefore, quite difficl;lt
to relate mathematically. It is desirable to list measurable or computable variabies
which effectively descr'lle the pro~esses occurring and then to reduce the hst by
makinl] simplifyin'] assumptions and cxamining relCltive ma,]nitudes of variables,
striving toward an acceptable balanl:e between accuracy and limitations of obtaining
datCl_ When this is done, the basic equar-1ons of fluid motion may be simplified (on
the basis of valid assumptions) Lo de~;cribe the phYSical modeL
!t~the ,ole of the succeedinq chapters to present these vClriables, define themJ
~ow_ how they interrelate, quantify their interrelations whe!".~..feasibleLClnd_,;i:1D",
bow they can be ~,d t.o achieve r_he successful rJesiqn of ri"~r erossinq,; and
encroachments.

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1.5.2 Basic Knowledqe Requir~

In order for the en<Jinecr to cOpe successfully with river engineering problems,

it is necessary that he has an adequate background in engineering with an emphasis

on hydrology, hydraulics, erosion and sedimentation, rivcr mechanics, sllil

mechanics, structures, economics, the environment and related subjects. In fact, as

the public has demanded more comprehensive treatment of river development

problems, the highway engineer should further improve his knowledge, and the

application of it, by soliciting the cooperative efforts of the hydraulic engineer,

hydrologist, geologist, <Jeomorphologist, meteorologist, mathematician, statistician,

computer programmer, systems engineer, soil physicist, soil chemist, biologist,

water management staFf and economist. Professional organizations requirin'] these

talents should be encouraged to work cooperatively to achieve the long range

research needs and goa.s relative to river development and application of knowledge

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