2.0 channels Flashcards
1
Q
two types of ditches
A
unlined conveyance ditches
lined
2
Q
advantages and dis of unlined conveyence ditches
A
seepage evap weeds polution livestock rodents, mosquitoes etc
advantages:
costs
large volume of water
3
Q
min free board
A
30-150 l/s 10 to 15 cm
150-300 l/s 15-20 cm
and so forth
4
Q
three sections of the stream corridor
A
terrace floodplain and hillslope
5
Q
lined ditches adv disadv
A
adv: prevent errosion long lasting control rodent damage reduce seepage reduce weed growth dependable water delivery
dis:
may be expensive
6
Q
types of lined ditches
A
geosynthetics
concrete
7
Q
limitations of using concrete
A
limited to sites with non expanding soil, good internral drainage
severe frosts , poorly drained, high sulphate conc
control cracks from shrinkage due to temp (contraction joints)
