micro drainage (flow/capacity) calculations for surface water drainage (project 314)

I am looking for a freelancer who can assist me in conducting micro drainage (flow/capacity) calculations for a surface water drainage project. The purpose of these calculations is to calculate the ATTENUATION CAPACITY of the drainage system. I have detailed drawings (layout, invert levels & attenuation volumes) for the dimensions and parameters of the drainage system, which will be provided to the freelancer. I also have a specific method/software in mind for conducting these calculations (micro drainage). It's a civil engineering software ... to do with fluid mechanics of how fast water moves down a drain pipe. Basically, they need to use the package to do the calculations ... there is also another autodesk product which will do the job also, think its called InfraWorks. However, I am open to discussing this further with the freelancer if they have alternative recommendations. The ideal freelancer for this project would have expertise in micro drainage / micro bore flow/capacity calculations and experience using the specific method/software that I have in mind. We have had a preliminary set of calcs done (only have the PDF output, no source to reuse), & have comment from the Local Authority that need to ensure 1 in 100 year storm + 40% climate change has no flood surcharge, with half drain time less than 24 hours. There is attenuation on the green roof, with all volumes at each level totaled up in the report, with a final attenuation tank before discharge off site. Flow restricted off site in last chamber. If we need to change our drainage drawing should different volume of attenuation be required, let us know & we can amend & reissue for calc to be updated with actual volume (as nearest storage cell module size may give more volume if added). Latest calc is one titled starting YW, original set file name starting FAIRHURST. Both included in case you have a need to refer back for something, but really treat it as a fresh calculation as both may have errors or assumptions. LPA (local planning authority) comments we need to address included as document. Note, this starts with their previous comments no longer relevant, then reviews & latest comments need to address are at the bottom (have highlighted). Any DWG files you require, let us know as we have them all available (as they are our drawings) but not included in advert to avoid confusion of too many documents. Calcs required for events 1:1, 1:30, 1:100 years + 40% climate change. Deliverables are calcs in PDF format, plus the source micro drainage software file for our records & in case required in future along with text note of engineers name, details & qualifications etc. to accompany calcs for local authority approval. All files are contained in the ZIP file for ease of download. Format of calculation MUST be as per [login to view URL] Prior to award, freelancers must demonstrate they are able to adhere to the format required, & supply a copy of a similar calculation they have done previously like our [login to view URL] ... this can be redacted to remove any information, details etc, we just need assurance that you will or can conform to the format required. Micro drainage source file to be supplied in addition to PDF for our records & project information. Solution may require modification of drainage design to be satisfactory, with mutual agreement of solution. Updated calculations to be supplied that certainly have no FLOOD outcome, nor SURCHARGE showing or predicted. Deadline for delivery of final correct file, with any corrections necessary (or updates to make solution work) to be 48 hours after confirmation of appointment & award.