This poetic description of the valley and the couple who are deeply absorbed not only by the grandeur of nature but of their sought-after togetherness as well, is truly enchanting. Alongside beauty and harmony, you have shown the discordance too, the inevitable clash in nature with the mention of a "distant shriek of a Peregrine Falcon" a hunter keeping up "nature's balance."
"the majestic valley" appears mystic as well, by creating "bliss of love" for them.
Usages, such as "wondrous sight," "nature's architecture" and " water chorused a calming reply" are figures that brilliantly bring out the best in nature.
edit-
"A small book below flashed brilliant shads of light, the water chorused a calming reply"
(A small brook below flashed brilliant shades of light, the water chorused a calming reply)
These are but slips that do not take away the ultimate beauty and charm of the grand spectacle of nature, you were lucky enough to enjoy and cherish.

Great nature poem!

Write on!