What do these small seal scripts say? It should be Xiaozhuan, right?

Excerpted from the poem "Jialing Water" in Yuan Zhen's Selected Poems. I don't know which calligrapher wrote the work. The signature seems to be: Geng? In the summer and month of that year, an author named Zhang was located in San? Made by the garden. The level is limited and I can only provide this little information. Please forgive me

Content of the seal script work: In ancient times, it should be the water at the top of the mountains, and the rivers have been flowing since ancient times. If the river flows to meet people's wishes, they should also know my intention from afar.