Q: Why is the City allowing the public to be misled into thinking that these proposals will stop flooding in the area?
“….. storms will still cause floods in the area downstream after the work is complete” “It should be noted that in the event of a storm, these works will not prohibit associated flooding from occurring.” (Hampstead Heath Management Committee Report)
Q: Why is there now suddenly a risk of total dam collapse?
Inspection reports by Supervising Engineer: July 2007; November 2012 both say:
‘There are no recommendation as to measures to be taken in the interests of safety’.
City FAQ sheet says: “Three of the ponds on the Heath are currently governed by the Reservoirs Act 1975. Their dams are safe and stable and regularly inspected by a statutory independent ‘Panel Engineer’.
“Are the dams safe? Yes. They are safe for the time being but will need work in the next two to three years to keep them safe.
“What has changed at the Heath to make this a problem now? Nothing physically has changed on the Heath, but altering weather patterns in the UK – long, dry spells followed by heavy rain storms – have created some serious floods in the UK in the last six years”
But these were not due to reservoir failures …. So what has changed?
Q: Why are only computer models used and all contrary factual evidence ignored
The Environment Agency states categorically that:
“… since 1925, there has been no loss of life due to dam disasters in the UK. …….. the likelihood of a complete dam failure is considered to be very low. The likelihood of flooding from a reservoir is far lower than from other forms of flooding.”
The Camden & GLC factual reports showing that flooding was concentrated along the lines of the GLC trunk sewers were brought to the attention of the City’s engineers, but dismissed as irrelevant.
Q: Why only total collapse scenario when the evidence shows that has never happened, not even in the 1975 storm
City FAQ sheet : “Risk: While the chance of a major flood is very, very slim, the potential consequences are very serious”.
Q: Modelling Uncertainty: Have the engineers taken this into account?
UNESCO website: http://www.unesco-ihe.org/urban-flood-management-and-disaster-risk-mitigation Urban Flood Management and Disaster Risk Mitigation Conference
“It is important to note that evolution of floods in urban areas is caused by several interrelated factors and as such modelling of their dynamics and impacts should not be considered as a precise activity”.
Q: Engineering risk
How can they be sure that: the scale of construction does not introduce an engineering risk; and it represents “building against nature” in a way antithetical to the ideal of the Heath. (Question raised in Consultation feedback)
Q: Why is there such variation in probable maximum flows (PMF)
“standard reservoir requirements”
City FAQ sheet: a one per cent chance of seeing every 100 years overflow can pass the 1:100 year flows,
City QRA talks of a PMF flood with a probability of 1 in 400,000 years
Q: Why is the City scaremongering about huge loss of life
City FAQ sheet: “A figure of c1,500 assumes no warning and a one-in-10,000 year inundation which could cause the dams to fail under the current spillway provision. If the proposed works were in place, and a warning given, the number falls to less than 100.”
“new hydrological studies show that the important ‘’’spillway’’ (or capacity for controlled overflow) is inadequate in the very rare and worst-case scenario of extremely heavy extended rain
Q: If this is really about saving life why is the City not working with Thames Water and Camden Council to co-ordinate
i. works to the area’s sewage and water systems, and
ii. develop robust early warning systems?
Met Office, Review by B. W.Golding 2007
“Long lead time flood warnings: “The ingredients are now available to build a future joint meteorology, ocean and hydrology forecasting and warning service providing enhanced lead time, accuracy and communication to the public and professional partners.”