The program of work covered a variety of geographical areas throughout the Scottish Water region. We have so far carried out assessments for eight developments ranging from small rural developments (Aviemore) to larger developments on the outskirts of cities (Holytown near Edinburgh). 

The DIA process involves the integration of a proposed development into the existing hydraulic model provided for that area.  Developments are modelled based on the following criteria:

• A population factor of 2.5 for each residential unit.
• A per capita water consumption rate of 165 l/hd/d.
• A baseflow equal to 10% of the developments calculated dry weather flow.
• A runoff equal to 1% of the development hard standing area in order to account for possible misconnections between the foul and surface water networks. 

A ‘like for like’ comparison of the baseline and development model is then carried out in order to predict the detrimental effects of the proposed development on the downstream system in terms of the following:

• Flooding
• Surcharge
• CSO spill frequency and volume
• Spill Setting

Dependant on the level of predicted detriment the Options may be developed in order to mitigate the detrimental effects of the development on the downstream system. 

RES are committed to the delivery of cost effective and sustainable solutions tailored to the needs of the client.