Dead Water Poem analysis

What does the dead water symbolize? What images are symbolized throughout the poem?

DEAD WATER

Here is a ditch of hopelessly dead water.
No breeze can raise a single ripple on it.
Might as well throw in rusty metal scraps
or even pour in left-over food and soup in it.

Perhaps the green on copper will become emeralds.
Perhaps on tin cans peach blossom will bloom.
Then, let grease weave a layer of silky gauze,
and germs brew patches of colorful spume.

Let the dead water ferment into jade wine
covered with floating pearls of white scum.
Small pearls chuckle and become big pearls,
only to burst as gnats come to steal this rum.

And so this ditch of hopelessly dead water
may still claim a touch of something bright.
And if the frogs cannot bear the silence---
the dead water will croak its song of delight.

Here is a ditch of hopelessly dead water---
a region where beauty can never reside.
Might as well let the devil cultivate it---
and see what sort of world it can provide.

-Wen Yiduo

In what way one see that the "hopelessly dead water" may have a bright touch?Why would the frogs croak in delight "when they cannot bear the silence?"