StormTac

Last updated: 2010-03-10

Flowchart (print screen) for the storm water model StormTac.

System requirements and user information

- Microsoft Excel 2000 or later is required.

- English is the model language (however it is from the flowchart possible to get a Swedish flowchart and translation of some words from English to Swedish).

- The number format in Windows must be points and decimals in the model must be written in points

Background

Metals and nutrients are examples of pollutants in storm water which may cause toxic and eutrophic effects in the receiving waters. StormTac is the tool that can help You towards a more sustainable storm water management. 

Areas of implementation

StormTac can help you to: 

• calculate storm water runoff volumes, pollutant concentrations and loads in the discharge points and from different land uses.
• compare measured/sampled data to calculated values.
• identify the largest pollutant sources and discharge locations to a recipient. 
• set up water and mass balances for receiving waters.
• estimate the acceptable recipient loads and the reduction needed.
• identify and decide where to implement Storm water Treatment Facilities (STFs) and detention facilities, such as wet ponds, filter strips, constructed wetlands, ditches/ swales and detention basins.
• choose and design (area and volume) STFs and detention facilities. 
• estimate the effectiveness of the designed STF or an existing STF and its effects on the recipient (reduced concentration values).
• calculate the capacity of storm water sewers.
• calculate loads from different pollutant sources such as wet and dry deposition, road wear, tyre wear, copper and zinc surfaces.

Some unique properties

1. simple to use (Excel 2000 format, taking advantage of VBA using clickable boxes and input forms in the flowchart).
2. requires little input data and no manual (help notes are included in the file), however a short manual that let you begin quickly (“within one hour”) with the calculations is included.
3. considers both point and diffuse loadings, base flow and atmospheric deposition.
4. integrates watershed and runoff properties with treatment/ detention facilities and impacts on receiving waters.

The model results are presented in a flowchart (see above), in tables and diagrams. They can also be and have been linked to other databases and GIS, see e.g.  http://www.tyreso.se/pubdoc/forv/msf/Kommunaltekniska/dagv/index.htm

Databases

StormTac includes databases with precipitation data, runoff coefficients, concentration data and reduction efficiencies.

 Required input data

The model requires very little input data. Watershed area (ha) per land use (e.g. houses, roads and forests) is the only obligatory input data. The traffic intensity (vehicles/day) is needed if studying the loads from larger roads within the catchment area. The area and volume of the receiving water are needed for estimating allowable loads. If the sub model “Source model” is to be used then added input data are road length (m) and material areas (m²). The included databases help to make more accurate analyses by letting you change other input data such as precipitation (mm/month or mm/year), runoff coefficients and water depths.

The model parameters can be calibrated to measured data to ensure site specific conditions being considered. In such cases further input data consist of measured flow (m³/year or m³/month), precipitation (mm/year or mm/month) and sampled concentration (mg/l or ug/l).

Calculation methods

The main methodology has been reviewed internationally through scientific papers and a doctoral thesis. The spreadsheet Excel model has been developed to automate the calculations by using land use specific standard values. It is best suited for long-term predictions. Runoff water flow is calculated from precipitation data and land use specific runoff coefficients and areas. Pollutant load rate (kg/year) is quantified from calculated flow and from standard concentrations. 

The standard concentrations are estimated empirically from a large set of flow proportional field sampling data, which contributes to their general applicability.

StormTac includes a large amount of sub models and equations for the design of different storm water facilities. The user can choose between a relatively detailed and a quick, simple design. The resulted dimensions by using different methods and by changing parameter values can easily be reviewed and compared. Examples of included design parameters are runoff coefficients, land use areas, facility permanent water depth, water depth of detention volume, slope, rain depth, outflow, emptying time and reduction efficiency.

The design methods have been employed for a large number of case studies from pre studies to final detailed construction drawings.

Case studies

StormTac has been used for example in the following case studies, where * indicates that calibration or comparison to measured data has been performed: Nybohov*, Stockholm (residential); Essingeleden*, Stockholm (road); Sätra*, Stockholm (residential); Lake Flaten*, Salem (residential); Flemingsbergsviken*, Huddinge (mixed); Tyresö municipality (mixed); Upplands Väsby municipality (mixed); Lake Edsviken and Lake Norrviken, Sollentuna (mixed), Lidingö municipality* (mixed); Karlstad municipality (mixed); Fittja, Botkyrka (residential); Reykjavik, Iceland (residential); Kaliningrad, Russia (road) and Lake Titicaca, Peru and Bolivia (mixed).

The table below presents standard, minimum and maximum concentrations for different urban and rural land uses. The standard concentrations should only be used when the storm water from the studied land use is average high, however else values closer to the presented min- or max-values should be used. The background colours indicate the level of uncertainty, based on the number of data values and their uncertainties.

Standard concentrations, StormTac, version 2010-03 New!

1. Standard

Land use	Runoff coeff.	P	N	Pb	Cu	Zn	Cd	Cr	Ni	Hg	SS	oil	PAH	BaP	COD	Fe	BOD	TOC	As	DOC	Cl	NH4-N	Fecal coliform	E. Coli	Alc.	Cond.	Fenoles
Urban	-	mg/l	mg/l	mg/l	mg/l	mg/l	mg/l	mg/l	mg/l	mg/l	mg/l	mg/l	mg/l	mg/l	mg/l	mg/l	mg/l	mg/l	mg/l	mg/l	mg/l	mg/l	mpn/100 ml	mpn/100 ml	mg/l	mS/m	mg/l
Roads (5 000 ADT)	0.85	0.14	1.7	14	31	62	0.24	1.0	1.2	0.060	79	0.17	0.67	0.030	25	1.4	5.0	21	2.4	21	13	0.70	1700	1900	28	12	6.0
Roads (10 000 ADT)	0.85	0.18	1.8	17	51	89	0.28	1.8	1.8	0.060	89	0.34	1.1	0.030	50	3.0	10	25	2.4	21	13	0.70	1700	1900	28	12	6.0
Roads (15 000 ADT)	0.85	0.20	2.0	21	59	116	0.30	2.6	2.5	0.060	95	0.50	1.1	0.035	65	3.5	12	26	2.4	21	13	0.70	1700	1900	28	12	6.0
Roads (30 000 ADT)	0.85	0.24	2.4	31	72	197	0.44	5.0	4.4	0.060	115	1.02	1.5	0.042	100	5.0	15	30	2.4	21	13	0.70	1700	1900	28	12	6.0
Roads (100 000 ADT)	0.85	0.31	4.5	80	94	575	1.0	16	14	0.060	206	3.40	2.0	0.14	225	8.0	25	47	2.4	21	13	0.70	1700	1900	28	12	6.0

Parkings	0.85	0.10	1.1	30	40	140	0.45	15	4.0	0.050	140	0.80	1.7	0.060	150	6.0	1.7	20	2.4	14	13	0.50	1900	1900	28	12	6.0
Houses	0.25	0.20	1.4	10	20	80	0.50	4.0	6.0	0.015	45	0.40	0.60	0.050	65	1.7	9.0	10	3.0	7.0	35	0.80	8345	700	28	12	2.0
Row houses	0.32	0.25	1.5	12	25	85	0.60	6.0	7.0	0.020	45	0.60	0.60	0.050	75	3.0	9.0	12	3.0	8.0	40	0.80	8345	700	28	26	3.0
Apartments	0.45	0.30	1.6	15	30	100	0.70	12	9.0	0.025	70	0.70	0.60	0.050	85	5.6	9.0	20	3.0	14	40	0.80	8345	700	28	7.9	4.0
Leisure houses	0.20	0.20	3.3	5.0	20	80	0.50	2.0	5.0	0.015	50	0.10	0.30	0.030	50	1.7	9.0	5.0	3.3	3.5	30	0.50	1900	700	28	25	2.0
Colony areas	0.20	0.15	5.0	5.0	15	50	0.20	0.20	1.0	0.012	38	0.10	0	0	50	1.7	9.0	5.0	3.3	4.0	20	0.50	1900	700	28	12	2.0
Commercial	0.70	0.28	1.9	20	22	140	1.0	5.0	8.5	0.050	100	1.50	0.60	0.10	60	1.6	11	24	2.4	17	40	0.50	4300	1900	28	12	6.0
Industry	0.50	0.30	1.8	30	45	270	1.50	14	16	0.070	100	2.50	1.0	0.15	80	8.0	9.0	24	4.0	17	50	0.50	2500	1900	28	9.7	6.0
Park	0.18	0.12	1.2	6.0	15	25	0.30	3.0	2.0	0.020	49	0.20	0	0	42	1.7	5.4	8.0	4.0	5.6	20	0.50	7200	700	28	14	1.0
Atmospheric deposition	-	0.032	1.5	3.0	5.0	30	0.11	0.17	0.40	0.010	0	0	1.9	0.010	19	0.050	2.5	4.0	0.30	3.0	0	0.80	0	0	0	0	1.0
Rural
Forests	0.050	0.035	0.75	6.0	6.5	15	0.20	0.50	0.50	0.0050	34	0.10	0	0	42	0.80	5.4	11	4.0	2.0	5.0	0.50	1000	700	28	12	1.0
Farmland	0.26	0.22	5.3	9.0	14	20	0.10	1.0	0.50	0.0050	100	0.15	0	0	42	0.80	10	13	4.0	9.0	10	1.0	1900	700	28	12	1.0
Meadows	0.075	0.20	1.0	6.0	15	30	0.30	2.0	0.50	0.0050	45	0.20	0	0	42	0.80	5.4	9.0	4.0	6.0	10	0.80	7200	700	28	12	1.0
Wetland	0.20	0.050	0.90	6.0	7.5	13	0.15	0.15	0.50	0.0050	16	0.10	0	0	42	0.80	7.5	11	4.0	8.0	5.0	0.30	1000	700	28	12	1.0
Other
Golf courses	0.18	0.35	2.1	5.0	15	18	0.30	0.70	2.0	0.010	55	0.20	0	0	42	1.7	16	4.0	4.0	8.0	20	0.50	1900	700	28	25	1.0
Airports	0.85	0.10	1.8	0.70	7.0	43	0.15	3.4	3.6	0.050	130	0.15	1.7	0.050	30	6.0	1.7	83	2.4	58	13	0.50	1900	1900	28	12	6.0
Railway area	0.50	0.053	1.0	26	49	168.75	0.32	2.2	1.6	0.050	56	0.60	2.0	0.050	42	0.80	5.4	10	4.0	10	40	0.50	1900	1900	28	12	2.0
Cutting area	0.050	2.0	6.0	7.0	15	0.20	0.50	0.50	0.030	0.0050	0.10	0	0	0	42	0.80	5.4	11	4.0	8.0	5.0	0.50	1000	700	28	12	1.0
Heat plant and deposit area	0.70	0.30	3.0	30	50	160	0.70	26	42	0.20	300	1.1	6.0	1.0	100	6.0	32	25	30	25	0	0.50	1900	1900	28	12	6.0
Waste plant	0.80	1.1	28	105	160	1350	2.1	26	42	0.20	92	1.1	6.0	1.0	1100	6.0	440	190	40	330	0	0.50	1900	1900	28	12	6.0
Harbour area	0.80	0.27	1.8	13	40	191	0.37	5.2	5.0	0.050	99	0.76	0.33	0.026	150	6.0	1.7	20	2.4	14	0	0.50	1900	1900	28	12	6.0
Petrol station	0.80	0.10	1.1	50	30	110	2.0	3.0	4.0	0.050	60	1.0	1.7	0.060	150	6.0	1.7	20	2.4	14		0.50	1900	1900	28	18	6.0
School area	0,45	0.30	1.6	15	30	100	0.70	12	9.0	0.030	70	0.70	0.6	0.050	85	5.6	9.0	20	3.0	14	40	0.80	1900	700	28	39	4.0
Athletic field	0,25	0.12	1.2	6.0	15	25	0.30	3.0	2.0	0.020	49	0.20	0	0	42	1.7	5.4	8.0	4.0	5.6	20	0.50	1900	700	28	19	1.0
Office area	0.70	0.25	1.5	30	30	140	0.90	13	7.0	0.10	100	1.3	1.0	0.15	42	1.7	16	4.0	4.0	5.6	40	0.50	1900	1900	28	12	6.0
Green area	0.075	0.065	2.0	4.5	11	20	0.25	0.25	0.50	0.0050	90	0.15	0	0	42	0.80	5.4	10	4.0	4.2	10	0.40	3000	700	28	12	1.0
Graveyard	0.18	0.050	1.0	6.0	20	25	0.30	2.0	0.50	0.0050	80	0.20	0	0	42	0.80	2.3	11	4.0	2	10	0.50	3000	700	28	12	1.0
Commercial, less dense	0.70	0.25	1.6	17	20	108	0.80	4.6	7.1	0.050	77	1.0	0.56	0.072	57	1.600	11	24	2.4	17	30	0.50		1900	28	12	6.0
Commercial, more dense	0.80	0.45	2.1	40	37	244	1.4	11	13	0.050	396	1.7	0.68	0.14	140	1.600	11	24	2.4	17	50	0.50		1900	28	12	6.0
Industry, less dense	0.60	0.29	1.6	25	35	214	1.1	9.6	12	0.060	80	1.7	0.82	0.11
Industry, more dense	0.60	0.42	2.2	50	79	402	2.1	16	22	0.080	220	3.1	1.8	0.21
Swimming house	0.70	0.30	1.6	15	30	100	0.70	12	9.0	0.025	70	0.70	0.60	0.050
House area for older people	0.30	0.30	1.6	15	30	100	0.70	12	9.0	0.025	70	0.70	0.60	0.050
Animal farm	0.20	0.45	3.0	6.0	15	30	0.30	2.0	0.50	0.0050	80	0.20	0	0
Shooting range	0.10	0.20	2.0	40	15	30	0.30	2.0	0.50	0.0050	80	0.20	0	0
Loading street	0.85	0.16	1.5	26	30	141	0.64	9.4	6.0	0.050	107	0.99	1.1	0.063
Detached houses with total LOD	0.15	0.16	1.2	6.0	14	64	0.30	2.8	4.8	0.010	25	0.26	0.36	0.060
Terraced houses with total LOD	0.18	0.20	1.2	7.2	18	68	0.36	4.2	5.6	0.015	25	0.39	0.36	0.060
Apartments with total LOD	0.22	0.24	1.4	9.0	21	80	0.42	8.4	7.2	0.020	39	0.46	0.36	0.060
Detached houses with LOD, not LOD for roads	0.18	0.25	1.8	13	25	102	0.64	5.1	7.6	0.016	57	0.51	0.76	0.13
Terraced houses with LOD, not LOD for roads	0.22	0.32	1.8	15	32	108	0.76	7.6	8.9	0.024	57	0.76	0.76	0.13
Apartments with LOD, not LOD fpr roads	0.28	0.38	2.0	19	38	127	0.89	15	11	0.032	89	0.89	0.76	0.13
Detached houses, less dense	0.15	0.16	1.2	6.8	17	68	0.42	2.8	4.4	0.010	35	0.28	0.56	0.072
Highway ditches	0.10	0.25	2.6	15	30	90	0.42	3.6	1.9	0.030	107	0.54	0.31	0.014
Metal waste area	0.80	0.30	3.0	22	120	153	0.32	1.9	5.6	0.020	13	33	6.0	1.0
Farm at farmland	0.15	0.20	2.0	5.0	14	50	0.20	0.20	1.0	0.0050	38	0.10	0.20	0.030
Roof	0.90	0.026	2.0	2.0	10	33	0.080	0.17	0.40	0.010	10	0	1.9	0.010
Fuel deposit	0.70	0.30	3.0	1.2	10	39	0.070	1.9	5.7	0.020	13	1.1	6.0	1.0
Green roof	0.31	0.032	2.4	3.0	10	30	0.11	0.17	0.40	0.010	20	0	1.9	0.010
Detached houses without road ditches, average	0.28	0.25	1.8	16	28	109	0.67	5.5	7.8	0.013	76	0.64	1.2	0.12
Detached houses without road ditches, min	0.25	0.18	1.5	11	20	90	0.27	3.8	6.0	0.048	48	0.50	1.1	0.027
Detached houses without road ditches, max	0.30	0.32	2.1	21	36	127	1.1	7.3	9.5	0.020	104	0.78	1.3	0.21
detached houses without road	0.19	0.20	1.5	8.0	21	90	0.27	3.0	5.0	0.048	40	0.35	1.5	0.019
Local street with curb stones	0.80	0.15	1.3	12	30	70	0.20	1.0	1.2	0.060	60	0.17	0.20	0.0070
Local street after reduction in open ditch	0.80	0.14	1.2	9.0	25	60	0.17	0.90	1.1	0.054	48	0.15	0.17	0.0060
Car dismantling area, impermeable	0.80	0.30	3.0	56	52	934	1.4	6.2	22	0.11	25	1.7	6.0	1.0
Deposit of asphalt etc	0.80	0.27	1.8	30	51	176	0.58	10	11	0.060	220	1.1	6.0	1.0

2. Minimum
Land use	Runoff coeff.	P	N	Pb	Cu	Zn	Cd	Cr	Ni	Hg	SS	oil	PAH	BaP	COD	Fe	BOD	TOC	As	DOC	Cl	NH4-N	Fecal coliform	E. Coli	Alc.	Cond.	Fenoles
Urban	-	mg/l	mg/l	mg/l	mg/l	mg/l	mg/l	mg/l	mg/l	mg/l	mg/l	mg/l	mg/l	mg/l	mg/l	mg/l	mg/l	mg/l	mg/l	mg/l	mg/l	mg/l	st/100 ml	st/100 ml	mg/l	mS/m	mg/l
Roads (<500 ADT)	0.70	0.14	1.2	5.0	20	60	0.20	1.0	1.2	0.060	40	0.17	0.20	0.0070	25	1.4	5.0	21	2.4	21
Parkings	0.70	0.070	0.60	11	25	50	0.20	3.0	1.0	0.050	40	0.50	0.40	0.040	100	6.0	1.7	20	2.4	14
Houses	0.20	0.10	1.0	2.0	12	50	0.30	1.0	2.0	0.015	20	0.10	0.50	0.030	40	1.7	9.0	10	3.0	7.0
Row houses	0.30	0.10	1.0	6.0	12	60	0.30	1.0	5.0	0.020	20	0.15	0.50	0.030	40	3.0	7.0	12	3.0	8.0
Apartments	0.35	0.20	1.0	8.0	12	73	0.30	5.0	5.0	0.025	40	0.20	0.50	0.030	60	5.6	9.0	20	3.0	14
Leisure houses	0.050	0.13	1.7	2.0	5.0	40	0.15	0.5	2.0	0.015	20	0.10	0.25	0.015	50	1.7	9.0	5.0	3.0	4.0
Colony areas	0.10	0.030	1.7	2.0	5.0	10	0.030	0.10	0.40	0.010	15	0.00	0	0	50	1.7	9.0	5.0	3.0	4.0
Commercial	0.40	0.20	1.2	10	17	60	0.50	4.0	5.0	0.050	42	0.30	0.50	0.030	57	1.6	5.0	24	2.4	17
Industry	0.50	0.28	1.4	20	20	130	0.50	3.0	5.0	0.070	50	0.50	0.55	0.040	40	8.0	8.0	24	4.0	17
Park	0	0.090	0.70	1.0	5.0	10	0.10	0.40	0.08	0.010	10	0	0	0	42	1.7	5.4	8.0	4.0	5.6
Atmospheric deposition	-	0.010	0.80	2.0	2.5	6.0	0.030	0.10	0.10	0.010	0	0	0.12	0.010	19	0.0080	2.5	4.0	0.10	3.0
Rural
Forests	0.050	0.015	0.40	1.0	4.0	10	0.10	0.10	0.030	0.0050	10	0	0	0	42	0.80	2.3	11	4.0	0.70