In PA10/04297 the Environment Agency and their website 'What's in Your Backyard' and Cornwall Council in their reasons for refusal all agreed the development site was in the flood plain. Back then building in flood plains was a bad idea and so development was refused planning permission. 

Environment Agency - Whats in your backyard TR27 4PS, by Environment Agency

Apparently now it isn't. 

Unless of course you use the flood warning maps, or the map in the Flood Preparation plan or the Flood Alerts warning system - in which case it is.

Current Alerts Map | Protect your home, business and family with UK Flood Alerts, by Environment Agency

Though the developer says it is in Floodzone 1 - just not Floodzones 2 or 3.

Since then the Environment Agency has twice been asked to uprate their risks and expand them - including the Met Office Review from September 2016 requiing a general 30% uprating.

And the site partially flooded in April 2016

But the Developer has produced a FRA which the Environment Agency say makes it all ok now.

Back in 2010 the Environment Agency looked at it rather differently - and also felt Loggans Moor would be a good choice of alternative site http://planning.cornwall.gov.uk/online-applications/applicationDetails.do?activeTab=consulteeComments&keyVal=L67K42FG0DE00

Environment Agency

Comment Date: Wed 17 Nov 2010

CONSTRUCTION OF SUPERMARKET, PETROL FILLING STATION, CAR PARKING, HIGHWAY WORKS, NATURE RESERVE AND ASSOCIATED WORKS (REVISED SCHEME OF W1/09-12730)
LAND AT MARSH LANE, HAYLE

I refer to your consultation on the above application and to the Sequential Test which you have prepared.

Environment Agency position
We OBJECT to this application for two reasons:
1. Flood risk Sequential Test.
2. Risk to controlled waters.


1. Sequential Test:
We object because the Sequential Test information prepared by you has demonstrated that there are reasonably available sites with less flood risk on which this development could proceed instead. We therefore recommend that the application should be refused.

Reasons
The application site lies within Flood Zone 3 defined by Planning Policy Statement 25 (PPS25) as having a high probability of flooding. Paragraph D5 of PPS25 requires decision-makers to steer new development to areas at the lowest probability of flooding by applying a Sequential Test. In this instance the evidence provided to indicate that this test has been carried out indicates that there are reasonably available sites at lower flood risk. Developing this site therefore fails to apply the sequential approach advocated in paragraph 14 of PPS25.

We agree with you that the South Quay site, South Quay site combined with the Jewson Site and the Hayle Rugby Club site are sequentially preferable in flood risk terms to the application site.

We note that you have accepted that the Loggans Moor and North Quay sites are sequentially less preferable than the application site though they both include an area within Flood Zone 1 which is greater than 2.3 hectares in extent. We would appreciate confirmation as to why these sites have been discounted.


2. Risk to Controlled Waters
We object to the proposed development as submitted because there is insufficient information to demonstrate that the risk of pollution to controlled waters is acceptable.
There are four strands to this objection. These are that:
we consider the level of risk posed by this proposal to be unacceptable.
the application fails to provide assurance that the risks of pollution are understood, as a preliminary risk assessment (including a desk study, conceptual model and initial assessment of risk) has not been provided. PPS23 takes a precautionary approach. It requires a proper assessment whenever there might be a risk, not only where the risk is known.
under PPS23 the application should not be determined until information is provided to the satisfaction of the local planning authority that the risk to controlled waters has been fully understood and can be addressed through appropriate measures. This is not currently the case.
There is a licensed abstraction (15/49/251/S/033 situated at National Grid Reference SW579385) that may be at risk from the development proposals, including from the operational phase. An assessment of risk to this and other identified receptors is required.

Reason:
To protect controlled waters.

I have kept the applicants agent informed with a copy of this letter.