Take my offer just as a way to contact you. I would like to talk with you and then have a chance to present my final offer.
I have been reviewing at your design. P1, P5, and P7 developments are located totally or partially at heights of 40 but the pumping stations seem to be located at 60. We need to relocate pumping stations to avoid 10 - 20 m depth excavations in the sewer network.
About the channel network. You have three lakes (north?) totally or partially located at the level 50 -60 but the one alone (south?), at 50 - 40. If you want to use gravity channels to ensure the water level of the total system, the lowest level in south lake will control the system so the north lakes will be 10 - 20 m below the surrounding terrain. -are those natural lakes?.
Finally, with respect to the Waste Water Treatment Plant - WWTP, be aware that WWTP detailed design has a commercial cost of USD80k - USD100k per 25k gpd and involves a multidisciplinary team. So, we need to clarify your expectations on this topic.
I look forward to a positive answer,