Watershed management divides one large drainage area into smaller planning units, and this question checks whether you know where the micro-watershed sits on that size ladder.
- 10-100 ha: this is the size given to the smallest unit on the ladder, the mini-watershed, so it is too small to be the micro-watershed.
- 100-1000 ha: this is the range that soil and water conservation planning assigns to the micro-watershed, the unit one step above the mini-watershed.
- 1000-10000 ha: this range belongs to the milli-watershed, a bigger grouping formed by joining several micro-watersheds.
- 10000-50000 ha: this range belongs to the sub-watershed, formed by joining several milli-watersheds, and is much larger than a micro-watershed.
Reading the ladder from smallest to largest as mini, micro, milli, sub, macro, the micro-watershed lands on 100-1000 ha, so option (2) is correct.
Let's summarize:
- Mini-watershed is the smallest unit, around 10-100 ha.
- Micro-watershed comes next, around 100-1000 ha, which is the answer here.
The area of the micro-watershed is 100-1000 ha, option (2).