1.2 Contact details of resource persons and institutions involved in the assessment and documentation of the Technology

Name of project which facilitated the documentation/ evaluation of the Technology (if relevant)

Constructed wetlands on agricultural drainage systems for enhancement of landscape´s water residence time and improvement of water quality (TH02030376)

Name of the institution(s) which facilitated the documentation/ evaluation of the Technology (if relevant)

Research Institute for Soil and Water Conservation (VUMOP) - Czech Republic

1.3 Conditions regarding the use of data documented through WOCAT

The compiler and key resource person(s) accept the conditions regarding the use of data documented through WOCAT:

Ja

1.4 Declaration on sustainability of the described Technology

Is the Technology described here problematic with regard to land degradation, so that it cannot be declared a sustainable land management technology?

Nee

Comments:

The described constructed wetland is a sustainable land management technology.

2.1 Short description of the Technology

Definition of the Technology:

A constructed wetland connected to tile drains that slows drainage flow, removes nitrogen and pesticides from drainage waters, and improves biodiversity. Formed from a substrate of matured birch chips and gravel, and is planted with reeds (Phalaris arundinacea) and reed manna grass (Glyceria maxima).

2.2 Detailed description of the Technology

Description:

This type of constructed retention wetland is designed to act in a natural way. The objective is to improve water quality, slow down runoff – and support biodiversity. It combines the functions of retaining, and gradually releasing, water while remediating (i.e. cleaning) drainage waters with a focus on pollutant of nitrates and pesticides. The wetland is established in connection with or directly on tile drains and is designed to have both subsurface and surface flow. The substrate used in construction is a mixture of 6-month matured birch chips (4-30 mm length) and gravel (4–8 mm diameter) at a ratio of 1:10. The wetland is planted with reed canary grass (Phalaris arundinacea) and reed manna grass (Glyceria maxima). The wetland to catchment ratio (WCR) is between 2:1000 and 3:1000: thus, for example, a constructed wetland of 200m2 or 300m2 would be required to serve an area of 10 hectares.
The process of establishing such a wetland begins with identifying where this measure is required. The drainage system must be thoroughly located and then the correct site for the wetland identified. The wetland is then designed and planned – including costs and labour requirements and the amount of land taken out of production. Administration includes processing statements and permission from state offices and landowners.

2.3 Photos of the Technology

2.5 Country/ region/ locations where the Technology has been applied and which are covered by this assessment

2.6 Date of implementation

Indicate year of implementation:

2018

If precise year is not known, indicate approximate date:

• less than 10 years ago (recently)

2.7 Introduction of the Technology

Specify how the Technology was introduced:

• during experiments/ research

3.1 Main purpose(s) of the Technology

• conserve ecosystem
• protect a watershed/ downstream areas – in combination with other Technologies
• preserve/ improve biodiversity
• reduce risk of disasters
• adapt to climate change/ extremes and its impacts

3.2 Current land use type(s) where the Technology is applied

Land use mixed within the same land unit:

Nee

3.3 Has land use changed due to the implementation of the Technology?

Has land use changed due to the implementation of the Technology?

• No (Continue with question 3.4)

Land use mixed within the same land unit:

Nee

Comments:

The current land use might change; e.g. if there was a meadow / cropland before and after implementation there is a wetland (i.e. water body or other surface)

3.4 Water supply

Water supply for the land on which the Technology is applied:

• rainfed

Comments:

Drainage fed wetland

3.5 SLM group to which the Technology belongs

• water diversion and drainage
• surface water management (spring, river, lakes, sea)
• wetland protection/ management

3.6 SLM measures comprising the Technology

3.7 Main types of land degradation addressed by the Technology

Comments:

Worsened drainage water quality (polluted by nitrates and pesticides). Accelerated (undue) subsurface runoff from farmland due to free-drainage.

3.8 Prevention, reduction, or restoration of land degradation

Specify the goal of the Technology with regard to land degradation:

• restore/ rehabilitate severely degraded land

4.1 Technical drawing of the Technology

4.2 General information regarding the calculation of inputs and costs

Specify how costs and inputs were calculated:

• per Technology unit

Specify currency used for cost calculations:

• USD

If relevant, indicate exchange rate from USD to local currency (e.g. 1 USD = 79.9 Brazilian Real): 1 USD =:

22.0

4.3 Establishment activities

	Activity	Timing (season)
1.	Identification of tile drainage (tiles, outlets).	anytime; project documentation, aerial images, field survey
2.	Water sampling (discharge + water quality) + Curve Number method application.	3-5x in several months. To get an overview of hydrochemical characteristics of the drainage and the volume of quick runoff
3.	Identification of a proper location for a constructed wetland (CW)	anytime; based on soils, land use, old maps, land owner/user situation, morphology, etc
4.	Assessment of CW hydraulic retention time (HRT) needed.	HRT is computed to enable removal of 50% of pollution load (e.g. NO3); based on average flow (m3/h), designed wetlad volume (m3) and substrate porosity (%)
5.	Design the CW	preparation of the whole documentation
6.	Administration and engineering of the CW	land owner issues, permissions, etc
7.	Construction of the CW	best in drier conditions
8.	Setting the plants	In central Europe - from April to September; at 0,5 - 1 m distance
9.	Finalization of the CW	grassing the banks, ground works, etc

Comments:

When designing the measures on land drainage at larger areas, there is a paper by Zajíček et al. (2022). How to Select a Location and a Design of Measures on Land Drainage – A Case Study from the Czech Republic. DOI: https://doi.org/10.12911/22998993/146270

4.4 Costs and inputs needed for establishment

If you are unable to break down the costs in the table above, give an estimation of the total costs of establishing the Technology:

48000.0

If land user bore less than 100% of costs, indicate who covered the remaining costs:

Municipality

Comments:

The cost for implementation of a CW is between 18 000 - 85 000 USD (48 000 on average), depending on the size, construction, equipment, etc.

4.5 Maintenance/ recurrent activities

	Activity	Timing/ frequency
1.	General Inspection	4-6 times per year (every two or three months)
2.	Removal / cleaning of sediment / cloggings	1-2 times per year (every six or twelve months)
3.	Removal of grass / biomass (if necessary)	2-6 times per year (every twelve or three months)

4.6 Costs and inputs needed for maintenance/ recurrent activities (per year)

If you are unable to break down the costs in the table above, give an estimation of the total costs of maintaining the Technology:

500.0

If land user bore less than 100% of costs, indicate who covered the remaining costs:

In our case research support; in practice could be Munucipality, Regional government, River Basin Management Authority

Comments:

The cost for maintenance/ recurrent activities of a CW is between 300 - 700 EUR per year (500 on average), depending on the size, construction, equipment, etc.

4.7 Most important factors affecting the costs

Describe the most determinate factors affecting the costs:

CW size, construction, equipment. Design of the whole CW - if designed as a more natural or rather a technical unit.

5.1 Climate

5.2 Topography

Indicate if the Technology is specifically applied in:

• concave situations

5.3 Soils

If available, attach full soil description or specify the available information, e.g. soil type, soil PH/ acidity, Cation Exchange Capacity, nitrogen, salinity etc.

Soil characteristics are not relevant, with an exception of the retention pond bottom and dam (best clay or low permeable soils).

5.4 Water availability and quality

Is water salinity a problem?

Nee

Is flooding of the area occurring?

Ja

Regularity:

episodically

Comments and further specifications on water quality and quantity:

The more often torrential rains are anticipated, the more attention is needed to pay to the design of the retention pond located prior the CW.

5.5 Biodiversity

5.6 Characteristics of land users applying the Technology

5.7 Average area of land used by land users applying the Technology

5.8 Land ownership, land use rights, and water use rights

Land ownership:

• communal/ village
• individual, not titled

Land use rights:

• communal (organized)
• leased

Water use rights:

• open access (unorganized)
• communal (organized)

Are land use rights based on a traditional legal system?

Ja

Specify:

land use / land owner might be different and must be taken into account (administrate)

5.9 Access to services and infrastructure

6.1 On-site impacts the Technology has shown

Socio-economic impacts

Production

Water availability and quality

Ecological impacts

Water cycle/ runoff

Biodiversity: vegetation, animals

6.2 Off-site impacts the Technology has shown

6.3 Exposure and sensitivity of the Technology to gradual climate change and climate-related extremes/ disasters (as perceived by land users)

Climate-related extremes (disasters)

Meteorological disasters

	How does the Technology cope with it?
local rainstorm	well

Hydrological disasters

	How does the Technology cope with it?
flash flood	well

Comments:

The design of a CW should consider to some extent also these risks - local rainstorms, soil erosion, etc. I.E. the technology must be designed and implemented with a regard to these phenomena; i.e. without loosing its effectiveness in such situations.

6.4 Cost-benefit analysis

How do the benefits compare with the establishment costs (from land users’ perspective)?

How do the benefits compare with the maintenance/ recurrent costs (from land users' perspective)?

6.5 Adoption of the Technology

• single cases/ experimental

If available, quantify (no. of households and/ or area covered):

This particular technology was applied only at several sites. However, there are dozens of intensive constructed wetlands on land drainage around the world (USA, New Zealand, Denmark, etc)

Of all those who have adopted the Technology, how many did so spontaneously, i.e. without receiving any material incentives/ payments?

• 0-10%

6.6 Adaptation

Has the Technology been modified recently to adapt to changing conditions?

Nee

6.7 Strengths/ advantages/ opportunities of the Technology

Strengths/ advantages/ opportunities in the land user’s view
Drainage water retention. Slowing down the loss of water from landscape.
Improvement water quality. Removal of reactive nitrogen and pesticides from drainage and related surface waters.
Enhancement of biodiversity. Promoting suitable sites for wetland flora and fauna.

6.8 Weaknesses/ disadvantages/ risks of the Technology and ways of overcoming them

Weaknesses/ disadvantages/ risks in the land user’s view	How can they be overcome?
Higher implementation costs.	Use as much local sources as possible. Work with the landscape, use old landsape patterns and experiences.

7.1 Methods/ sources of information

7.2 References to available publications

Title, author, year, ISBN:

FUČÍK, P., VYMAZAL, J., HNÁTKOVÁ, T., ŠEREŠ, M. (2018): A trial constructed wetland on agricultural drainage systems for enhancement of landscape´s water residence time and improvement of water quality. In konference 16th IWA International Conference Wetland Systems for Water Pollution Control (http://icws2018.webs.upv.es/conference/about-conference/ ), 29.9. - 4.10.2018, Valencie, Spain.

Title, author, year, ISBN:

VYMAZAL, J., SOCHACKI, A., FUČÍK, P., ŠEREŠ, M., KAPLICKÁ, M., HNÁTKOVÁ, T., CHEN, Z. (2020): Constructed wetlands with subsurface flow for nitrogen removal from tile drainage. Ecological Engineering 155 (2020) Article number 105943: 1-10. ISSN 0925-8574. https://doi.org/10.1016/j.ecoleng.2020.105943

Title, author, year, ISBN:

Fučík P., Vymazal, J., Šereš, M., Hejduk, T., Hnátková, T., Sochacki, A., Kulhavý, Z., Zajíček, A., Zhen, Z., Duffková, R., Kaplická, M., Sítková, V., Poláková, V., Kukačka, J. 2021. Constructed wetlands on land drainage – principles for design, placement and operation for enhancement of water residence time and improvement of water quality – A certified methodology. Prague. ISBN 978-80-88323-50-1 (print version), ISBN 978-80-88323-51-8 (online pdf). In Czech.

7.3 Links to relevant online information

Title/ description:

Constructed wetlands on agricultural drainage systems for enhancement of landscape´s water residence time and improvement of water quality

URL:

https://starfos.tacr.cz/en/project/TH02030376

7.4 General comments

This is the end.