Define Rock fill dam.

In our country, there are attempts to increase the height of several existing dams like Tehri and Almati, dams across Narmada. Choose the correct statements among the following that are a consequence of raising the height of dams

$\left(i\right)$ Terrestrial flora and fauna of the area is destroyed completely.

$\left(ii\right)$ Dislocation of people and domestic animals living in the area.

$\left(iii\right)$ Valuable agricultural land may be permanently lost.

$\left(iv\right)$ It will generate permanent employment for people.

It is important to make small check dams across the flooded gullies because they

$\left(i\right)$ hold water for irrigation

$\left(ii\right)$ hold water and prevent soil erosion

$\left(iii\right)$ recharge ground water

$\left(iv\right)$ hold water permanently