Scottish Surface water storage volume estimation tool

The surface water storage volume estimation tool provides both greenfield flow rate estimates for setting limiting discharge rates as well as surface water storage attenuation volume estimates for use in initial drainage design. The tool is designed to be used with a minimum of information by users who need not be drainage engineers.

How to use the tool

To use the Surface water storage volume estimation, enter the postcode where your site is located and then click on the map to extract the site coordinates and related hydrological characteristics. The tool lets you enter your own values so that you can compare them with the map values. Once all fields are completed you can save your data to generate a pdf.


Site address

Enter the postcode where your site is located and click the Search button. You can then click on the map to extract the site coordinates and related hydrological characteristics.
Alternatively you can directly zoom in the map and click on the exact site location.


Site latitude  
 

Site details

 
 

Site characteristics

 
 
 
 
 
 
 
 
 
 
 
 
 

Hydrological characteristics

These data come from the click on the map. The values on the left can be edited.
  My values Map values
 
 
 
FEH/FSR conversion factor  
Hydrological region  

Design criteria

   
 
 
 
 

Select method to calculate surface water storage requirements

IH24 method

IH124 specifically addresses the runoff from small catchments (Institute of Hydrology, 1994). Although shown to be slightly less accurate than more recent FEH based methods, it is still considered to be an acceptable approach for assessing greenfield runoff rates. For more information on the IH124 method, check out our FAQ.

Input fields for the IH124 method

Enter criteria needed to calculate surface water storage requirements with the IH124 method.

1. Growth curve factors
  My values Map values
Growth curve factor 1 year
Growth curve factor 10 years
Growth curve factor 30 years
Growth curve factor 100 years
Growth curve factor 200 years
2. Derivation of Qbar
   
 
   
 
  My values Map values
Specify SOIL type  
SPR  
3. Rainfall input
Please update these values with FEH13 rainfall values if available
Rainfall 100yrs 12hrs (mm)  
Rainfall 200yrs 12hrs (mm) Note: this input is only a requirement for 200 year storage volume estimation for Scotland

Results using the IH24 method

Estimated site discharges
  My values Map values
 
Qbar (l/s) 
1 in 1 year (l/s) 
1 in 30 year (l/s) 
1 in 100 years (l/s) 
1 in 200 years (l/s) 
Estimated storage volumes
  My values Map values
Interception storage (m3
100 year Attenuation storage (m3
200 year Attenuation storage (m3
100 year Long term storage (m3
Treatment storage (m3
Total storage (m3

FEH method

The FEH statistical equation predicts the median annual flood called Qmed (a return period of 1:2 years).

More information on the FEH method and the equation it uses, check our Frequently Asked Question.

FEH input fields

Enter criteria needed to calculate storage water requirements using the FEH method.

1. Growth curve factors  
  My values Map values
Growth curve factor 1
Growth curve factor 10
Growth curve factor 30
Growth curve factor 100
Growth curve factor 200
2. Derivation of Qmed and Qbar
The FEH method calculates Qmed and converts this to Qbar via a conversion factor. The tool can estimate Qmed from BFI and SAAR via the FEH equation or you can specify it manually.
 
Enter Qmed (l/s)
3. Rainfall input
Please update these values with FEH13 rainfall values if available
Rainfall 100yrs 12hrs (mm)  
Rainfall 200yrs 12hrs (mm)  

Results using the FEH method

Estimated site discharges
  My values Map values
Qbar (l/s)
1 in 1 year (l/s)
1 in 30 years (l/s)
1 in 100 years (l/s)
1 in 200 years (l/s)
Estimated storage volumes
  My values Map values
Interception storage (m3)
100 year Attenuation storage (m3
200 year Attenuation storage (m3
100 year Long term storage (m3
Treatment storage (m3
Total storage (m3)

ReFH2

The ReFH2 peak flow rates for the 1 year, 30 year and 100 year return periods can only be obtained by first visiting using the ReFH2 website. This information, along with a few other parameters, need to be entered into the UKSuDS tool for estimating storage requirements used these flow rates.

Input fields for the ReFH2 method

1. Flow inputs
Qmed (l/s) (whole site area)
Q1 (l/s)
Q30 (l/s)
Q100 (l/s)
Q200 (l/s)
2. Rainfall inputs
Rainfall 100yrs 12hrs (mm)  
Rainfall 200yrs 12hrs (mm) Note: this input is only a requirement for 200 year storage volume estimation for Scotland
3. Soil input
 

Results using the ReFH2 method

Estimated site discharges
  My values Map values
Qbar (l/s)
1 in 1 year (l/s)
1 in 30 years (l/s)
1 in 100 years (l/s)
1 in 200 years (l/s)
Estimated storage volumes
  My values Map values
Interception storage (m3)
100 year Attenuation storage (m3
200 year Attenuation storage (m3
100 year Long term storage (m3
Treatment storage (m3
Total storage (m3)

This version of the surface water storage volume estimation tool is for users for whom the map functions on the UK SuDS site do not work correctly.

The help and support information that is provided on the main site is not available here. Please visit UK SuDS for instructions on how to use this tool.