River flow is a renewable natural resource of stochastic (unstable) character, changing both within a year and over the years.
(River flow; is; a renewable natural resource of stochastic (unstable) character) (stochastic (unstable) character; changing; both; T:within a year and over the years)
River flow stochastic (unstable) character
is changing
a renewable natural resource of stochastic (unstable) character
both T:within a year and over the years