23: Potentials for increased infiltration in new urban areas

Activity C23 Potentials for increased infiltration will gain from action C3. In selected areas a detailed local model is set up focusing on groundwater, surface and/or seawater. Models are based on the present data and collections of new data sets e.g geophysical data and C23 will benefit from the outputs of his model and its implementation under different actions, thereby improve mapping of the infiltration potential in urban development areas .

Under Action C4 Rainwater, C23 will gain from the identification and experience of different setup models and testing of SUDS within CDR. Action C7 will aim at gathering useful information and best practices from cross-cutting demonstration activities and stakeholder processes. C23 will benefit directly from these actions.

Linked to Complementary Actions

Horsens and VIA expect subsequently to design and realise complementary projects, with a focus on examining how water delaying measures can be integrated with SUDS solutions. Danish Eco-Innovation Programme (MUDP) and similar national funds are potential sources of financing. The amount of financing sought is DKK 1-2 million.

The outset of this action is sustainable Climate Change Adaption through a holistic sustainable concept, with a specific focus on increased infiltration in urban areas, in particular new urban development areas.

As with other towns and cities in Denmark, Horsens faces future climate challenges in the form of more frequent and intensive precipitation.

Towns and cities are vulnerable to climate changes, and preventative efforts are required to protect urban areas from intense rainfall events, which may lead to flooding and subsequent damage to buildings and infrastructure.

Subsequently, expenses for handling surface water are increasing significantly in most municipalities. It is therefore in the interests of the municipalities as far as possible to manage infiltration locally, thereby disconnecting surface water completely or partially from the sewer system.

However, with regard to the establishment of new urban development areas, at present it is difficult for the municipality to give firm advice to developers on where and how to management surfacewater by infiltration. This is partly due to the lack of basic knowledge of the soil’s infiltration capacity. Thus, infiltration solutions are presently established only in areas without a risk to the groundwater and domestic water resource, and the surrounding recipients. This limits the use of infiltration in many towns and cities.

Action C23 involves three sub-actions:

• C23.1: Mapping of the infiltration potential in urban development areas
• C23.2: Integrated stakeholder process
• C23.3: Definition of complementary projects

What:
The Horsens city and its suburbs is the project area for this action, covering the possibilities of infiltration of surface water in urban development areas throughout the municipality’s urban development areas.

For the purpose of mapping the infiltration potential in urban development areas, areas will be mapped with high-precision geophysics, which may show in detail the upper 5 to10 meters of the ground surface, see Figure 50 and Figure 51. In connection with the geophysical mapping, supplementary manual drillings up to 1 to 5 meters depth will be carried out, describing lithology and grain size analyses in detail.

As an extension of the geophysical mapping, infiltration tests cf. Figure 52 are made with different clay types found in urban development areas. The aim is to carry out field studies to a sufficient degree, making it possible to perform a quantitative (statistical) clarification of the individual soils’s infiltration capabilities. The results of the executed infiltration tests form the basis for examining to what extent there exists a quantitative correlation between the geological descriptions and the soils’ infiltration capabilities.

Similarly, the resistivity measurements from the geophysical mapping will be compared with the results from the infiltration tests, to ascertain whether a quantitative correlation exists between the deposits’ electric resistivity and the infiltration capabilities. Based on the soil types’ different infiltration capabilities, it will be possible to produce a detailed infiltration potential map for urban development areas.

How:
Action C23.1 includes:

1. Quantitative (statistical) clarification of the individual soil’s infiltration capabilities. By finding a quantitative correlation between the individual soil type and their infiltration capabilities, results can be immediately transferred to similar areas, for example, with the use of a soil type map.
   
   
2. Quantitative correlation between the geological descriptions from the drillings and the soils’
   infiltration capabilities. By finding a quantitative correlation between the geological descriptions from drillings and the soils’ infiltration capabilities, stakeholders and municipalities have the opportunity in the future to be able to express whether the area’s infiltration capabilities are valid based on new and existing descriptions from drillings.
   
   
3. Quantitative correlation between the soils’ electrical resistivity and infiltration capabilities. By finding a quantitative correlation between the soils’ electrical resistance and their infiltration capabilities, stakeholders and municipalities are in the future able to carry out geophysical mapping and thus gain an overview of the area’s infiltration potential.
   
   
4. Production of a detailed infiltration potential map for urban development areas. In connection with the preparation of a infiltration potential map, a number of guidelines will be written, which describe how the map is made and which data are necessary.
   
   
5. The creation of a professional knowledge base for the municipalities’ formulation of best practices and guidelines for local management of precipitation in urban development areas. Reports on best practices and guidelines that describe how data shall be used and interpreted. The results will be reported to other municipalities and stakeholders with similar challenges on an ongoing basis, so that experience from the project can be passed on and widely dispersed.

Where: Horsens city and suburbs is project area. However, the methodology developed is relevant for all C2C CC partners. The project area covers approx. half of a total of 490 ha, where Horsens has designated development areas for new homes. See Figure 53.

When: January 2017 – December 2018 

Phase 1:
It is planned that action C23.1 will be executed over the first two years (2017-2018)

What
Relevant stakeholders from public sector (municipal staff and utility company) and private sector (developers, citizens and consultants) will be involved in in an integrated stakeholder process, where technical results will be transformed and disseminated through field trips, workshops and subsequent development of description of best practices and guidance for stakeholders on how to best make use on infiltration of surface water in future urban development projects.

How
C23.2 is carried out in collaboration with local stakeholders, landowners, citizens, developers, municipal and utility company employees and knowledge institutions with an interest in, knowledge of and experience on developing new urban areas, sewer and surface water systems

C23.2 will be carried out through:

1. Stakeholder process (landowners, citizens, municipal and utility company employees and knowledge institutions).
   
   
2. Review of the results from the current project and how they can be used in the future.
   
   
3. Execution of a workshop, where we discuss the advantages, disadvantages, possibilities and consequences of the results from action C23.1.
   
   
4. Preparation of recommendations for best practices and guidance for stakeholders related to future working processes for the purpose of mapping the infiltration potential in urban areas.

Where: In specific areas designated for urban development throughout the municipality.

When:
Phase 2 and beyond: January 2019 – December 2019.

What
Stakeholders involved throughout C23.1 and C23.2 will be invited to share experience, ideas and knowledge on how to use the new techniques for identifying and developing new urban areas using infiltration as primary means of managing surface water. Subsequently, new knowledge and ideas will be combined with other complimentary projects to form the basis of applications for new projects with external co-funding for the Eco-Innovation fund and similar funds.

How

1. Final stakeholder conference, where the results are presented to other municipalities and stakeholders facing similar challenges. In this way, it is ensured that experiences from the project are passed on and widely integrated. The intention is to hold the conference under the auspices of the Danish EnviNa organsaition or in similar international fora.
   
   
2. Prepare complementary projects based on the results.
   
   
3. Initiate complementary projects with external co-financing.

Where: In Horsens and at VIA, Horsens.

When:
Phase 2 and beyond

The project is necessary for the municipalities and stakeholders, as they will acquire a number of tools that may determine accurately, where surface water may be managed locally in future urban development areas.

Results will create added value and business development for municipalities and stakeholders, since they will be able to prioritise efforts for managing surface water and thus achieve more sustainable Climate Change Adaption solutions.

In addition, the municipalities and stakeholders will acquire concrete knowledge on how a new local area may be screened quickly, efficiently and cheaply for the potential of infiltrating surface water.

The project makes it possible to form a solid knowledge base, enabling a choice of more sustainable and holistic Climate Change Adaption for the benefit of society, citizens and the area’s biodiversity, as more green solutions may be implemented.

The project’s results and guidance will be assessed, partly to be able to be used by other sub-projects under the auspices of C2C CC and to support networking and knowledge sharing across municipalities, utilities and other climate players, and partly to contribute to innovative complementary projects, benefiting a broader group of stakeholders in Denmark and in the EU.

C23.1 may be constrained by lack of involvement by local stakeholders. This is dealt with by explicitly presenting problems resulting from climate changes to the local stakeholders, and by showing the knowledge base the project may give to the stakeholders, the timeframe and potential financial advantages that the project offers clear to the stakeholders e.g. by avoiding costs for sewage piping. As far as possible, we will utilise experts from the C2C CC knowledge committee.

C23.2: assumption that stakeholders support the results of C23.1. This is dealt with by ensuring the results and associated consequences are broadly disseminated and clear for everyone.

C23.3 may be constrained by limited funding for a complementary project. We will early in the process engage with relevant representatives from public and private funds, who may find an interest in funding subsequent follow-up activities.

Through a participatory stakeholder process, field trips and workshops, C23 will ensure a timely and integrated local participation in the areas, where urban development and surface water management using infiltration will take place. The work will be broad in relation to new techniques and new approaches (giving added value).

Together with experts C23 will produce relevant maps and reports on how and where to infiltrate and give advice on how to manage the processes towards a better management of surface water and infiltration.

C23.1
Defined methodology on the correlation between soil type and infiltration potential to be replicated in Denmark and Northern EU. App. 320 infiltrations tests. App. 250 hectares geophysical mapping. App. 100 hand drillings and soil samples descriptions. Full overview of infiltration potentials in Horsens municipality. Integrated municipal plan in Horsens on how to use infiltration for future urban development.

C23.2 
200 stakeholders actively involved, and knowledgeable about best practices. New guidelines used for planning water management in at least 5 new urban development areas.

C23.3 
Funding assured for at least one new project of min 5 million DKK.

C23.1 will have expenses for external expert consultation in connection with geophysical mapping. It is expected that approx. 18 ha/day can be mapped, which gives a total of 14 days in the field. In addition, it is expected that 320 infiltration tests will be carried out.

Expenses for external expert consultation are expected to be DKK 400,000, based on inquiries.

In connection with C23.1 it is expected that Horsens Municipality and VIA University College will contribute by providing advice, execution of drillings, data processing and the interpretation of data. Horsens Municipality will contribute with 100 hours and VIA 1704 hours. In connection with project C23.2. it is expected that Horsens Municipality and VIA University College will contribute by providing information, reporting and meeting activity in collaboration with stakeholders.

In connection with project C23.3, it is expected that Horsens Municipality and VIA University College will contribute by providing information, reporting, planning of workshops and the final conference. For Hedensted Municipality the total number of person-days per year is based on the basis of the total working hours/days according to national legislation, collective agreements, employment contracts, etc. – budgeted at 214 days per year.

Subsistence costs are based on prior experience and can be further subdivided into Hotel costs, Daily allowances/Payment for meals and local transportation categories, as shown below for this action’s subsistence costs items:

C23.1

• 1 report on Quantitative (statistical) clarification of the individual soil’s infiltration capabilities by soil type mapping. 
• 1 report on Quantitative correlation between the geological descriptions from the drillings and the soils’ infiltration capabilities.
• 1 report on quantitative correlation between the soils’ electrical resistivity and infiltration capabilities.
• 1 report on detailed infiltration potential map for urban development areas of Horsens.
• 1 guideline with process description of how the infiltration potential map can be prepared.
• Final report on C23.1

C23.2

• Reports on best practices and guidelines for local management of precipitation in urban development areas.
• Stakeholders workshop. Report, which is published on the C2C CC website.
• Articles for international periodicals
• Results will be presented at conferences in Denmark and abroad.

C23.3

• Knowledge sharing across municipalities and stakeholders.
• PPT. Presentations published on the C2C CC website.
• Complementary project description.

C23.1

Phase 2:

31/12/2019: Report on quantitative clarification of the individual deposit’s infiltration capabilities finalised.
31/12/2019: Report on quantitative correlation between the geological descriptions from the drillings and the deposits’ infiltration capabilities finalised
31/12/2019: Report on quantitative correlation between the deposits’ electrical resistivity and infiltration capabilities done.
31/12/2020: Infiltration potential map for the urban development areas done.
31/12/2020: Full overview of infiltration potentials in Horsens municipality finalised.
31/12/2020:Integrated municipal plan in Horsens on how to use infiltration for future urban development drafted 

C23.2

Phase 2:
31/08/2020: Meetings with 200 stakeholders done
31/08/2020: One field trip to selected sites done
31/08/2020: Stakeholder integration of 200 stakeholders done
31/12/2020: Workshops held and working groups met. 
31/12/2020: Recommendations Reprepared for stakeholders 

C23.3

phase 2 and 3:
31/12/2021: Final stakeholder conference. 200 participants
31/12/2021: At least one pilot projects prepared.
31/12/2021: At least one project description ready for execution.
31/12/2021: Final review of the project done