It is recommended that WAF approve the detailed design of the proposed watermain alignment as shown on the construction drawings and allow this project to proceed to the construction stage as a matter of urgency so that the laying of the new DN375mm mPVC pipe can commence.  And that the stream crossing options be further investigate and a recommendation be prepared presented to WAF for approval at a later date.  

第一句

It is recommended：It形式主语+被动语态谓语。recommend要求that从句用虚拟语气。

that WAF approve the detailed design of the proposed watermain alignment as shown on the construction drawings and allow this project to proceed to the construction stage as a matter of urgency so that the laying of the new DN375mm mPVC pipe can commence为that引导的真正主语从句。其中：WAF为主语，approve谓语1（动词原型式虚拟语气），the detailed design of the proposed watermain alignment宾语，as shown on the construction drawings过去分词短语作后置定语，and allow谓语动词2（虚拟语气），this project宾语，to proceed to the construction stage不定式短语作宾语补足语，as a matter of urgency介词短语作方式状语修饰to proceed, so that the laying of the new DN375mm mPVC pipe can commence目的状语从句修饰谓语allow。

第二句

这个句子只是并列的两个that从句，从句中都是动词原型。对此可以有两种解释：1 承前省略了it is recommended。2 与上一句最后的目的状语从句并列的目的状语从句（so省略），后一个从句so和that均省略。动词原型可理解为承前省略了can，也可理解直接用原型动词作谓语（目的状语从句的虚拟语气）。

that the stream crossing options主语 be further investigated被动语态谓语 and a recommendation 主语 be prepared被动语态谓语1 and presented被动语态谓语2 to WAF方向状语 for approval at a later date目的状语.