The rocks here somehow look as if they have been newly installed along with the newly paved walkways, newly planted trees and other design elements along the blueway, but actually they've been there since the Yuyan Middle School across the road to the east was built in 2006.
In mid-2023 the Yuyan Middle School (玉岩中学) is getting an overhaul and upgrade of the building facades of all the school buildings. It's amazing how many high status, high fee and selective middle schools have been set up in the area, complete with impressive sports facilities too. In the older parts of the city people buy apartments near such schools so their children can get preferential access, but in Huangpu this practice is made difficult by the fact that many of them are located on huge and sometimes relatively isolated campuses with few or no nearby apartment buildings. This school does have a cluster of highrises across the road to the south, one of which is a luxury apartment building. Immediately to the east of Yuyan is the Guangzhou Development Zone No. 1 Kindergarten (广州开发区第一幼儿园(中心园) and the Whampoa Radio and TV University (黄埔广播电视大学).
The highest profile schools here with the most impressive facilities nearly all seem to be offshoot campuses of existing established schools in older parts of the city. Yuyan School's original campus was established in 1940 in Yuexiu District. The Science City Middle School across the river here is presumably an exception.
The blueways often feature a kind of redundancy with multiple pathway options in parallel, in this case along both sides of the canal and at both the road level and lower down. It's not necessarily the most efficient approach but it works well, and ensures that the area down by the cache is usually pretty quiet and sheltered from passers-by.
PS from March 2023: The container includes a Covid test kit in commemoration of the end of the zero covid mania in late November/ early December 2022, around the time this cache was hidden.