But irrigation entailed the risk that human digging of ditches and canals could lead to sudden heavy water runoff from rainstorms, digging further down into the ditches and canals and carving out deep channels called arroyos.

与 digging further down into the ditches and canals and carving out deep channels called arroyos 并列的成分是什么？这句话怎么翻译？

【翻译】但是，水利灌溉需要冒风险，就是人类挖掘沟渠和运河可能会导致大暴雨的突发性强水流，结果使那些沟渠和运河掘进更深，开掘出深深的通道叫做沟壑。

【分析】that从句跟the risk是同位语。

1. digging further down into the ditches and canals and carving out deep channels called arroyos：现在分词短语作结果状语。

2. 其中，digging further down into the ditches and canals与carving out deep channels called arroyos是并列。

3. called arroyos作定语修饰deep channels。