It can generate hydroelectric power. 

It also reduces the risk to natural and climate hazards, by protecting from flood episodes, provides a regulated amount of water to surrounding areas for irrigation. Dams provide water balance in cases of extreme or irregular weather. It also contributes to a better water management, by offering the possibility to displace the water to dry areas when there are floods.

It allows community to collect fresh water during rainy seasons for later use during droughts and dry spells, as well as provides water balance in case of extreme/irregular weather.

It contributes to enhancement stability of the urban infrastructure, it may improve pedestrian access though footpaths, and it may offer facilities for anglers and mooring provision for the recreational and holiday boating industry.

Another co-benefit is related to species increase, enhancing wetland habitats. It can also lead to an improvement in the extent and quality of natural habitats, and contriibutes to minimize losses due to floods.

Political:

Alignment among stakeholders: planning authorities, developers and landowners.

Economic:

The primary cost are land acquisition and maintenance.

Social:

The effective planning, design, construction and operation of urban Natural Water Retention Measures requires the involvement of a wide range of stakeholders.

Technical:

Dimensions: retention of sediment behind the dam wall alters minimally the course of the water to avoid flooding. Not compatible with traditional solutions at historic centres and highly dense consolidated urban areas. Not possible to be implemented in case of existing underground facilities.

Legal:

National and local instruments are the most widely effective for SUDs due to their wide-scale application at the household or very local level. Existing standards facilitate the development of the solution.

Political:

No interaction between authorities and other stakeholders, lack of commitment, society pressure to avoid its construction.

Economic:

Depends on resources availability for the investment, which is usually expensive.

Social:

No participation to enhance the solution, no acceptation of society, displacement of the population, loss of vegetation.

Technical:

Lack of territory suitability, geomorphology, excessive elevation, small place.

Legal:

No planning instruments that support, prohibition to construct there due to protection regulations.

Geographic:

Conditioned by place, geomorphology and scale of implementation – there may be restrictions depending on the space to be implemented (urban x rural areas, dense x dispersed zones, etc.)

This type of interventions has a very high cost, and it is difficult to get the investment recovery in a short term. The interventions usually create important modifications in the environment.

• Hard drainage-flood prevention (URBAN GreenUP project)
• Remus, J. I., & Jonas, M. (2010). River Engineering: Past, Present and Future–A Comprehensive Systems Approach
   

Protecting the community against floods and landslides, it contributes to the decrease of the potential vulnerability.

DNSH – it contributes positively to the following objectives:

• Climate change adaptation
• The sustainable use and protection of water and marine resources
• Pollution prevention and control to air, water or land
• The protection and restoration of biodiversity and ecosystems

• High level engineering knowledge to develop the project and implement the hard drainage.
• Training of involved stakeholders
• Incentives
• Voluntary measures with stakeholders
• Regulation and standards in place

• REgional flood management by combining sof and hard engineering solutions, the Norfolk Broadlands (Climate Adapt)
• Hard drainage-flood prevention (URBAN GreenUP project)
• Remus, J. I., & Jonas, M. (2010). River Engineering: Past, Present and Future–A Comprehensive Systems Approach
• Hard drainage-flood prevention (URBAN GreenUP project) Remus, J. I., & Jonas, M. (2010). River Engineering: Past, Present and Future–A Comprehensive Systems Approach