Interview Questions for Drainage Control

Hydraulics, the study of water flow, is fundamental to drainage control. Understanding principles like flow rate (Q), velocity (V), and pressure (P) is crucial. The continuity equation (Q = AV, where A is the cross-sectional area and V is the velocity) dictates that flow rate remains constant in a pipe of uniform diameter, influencing pipe sizing. Bernoulli’s equation, stating that the sum of pressure head, velocity head, and elevation head remains constant along a streamline, helps determine energy losses due to friction and changes in elevation. These principles guide the design of efficient and effective drainage systems, ensuring adequate capacity to handle anticipated water flow and prevent flooding. For instance, a poorly designed system might ignore friction losses, leading to undersized pipes and inadequate drainage.

Imagine a simple downspout draining a roof. The flow rate depends on the roof area and rainfall intensity. Bernoulli’s principle explains why water flows faster at the bottom of the downspout (higher velocity head due to lower elevation head). Understanding these principles allows us to select appropriate pipe sizes and slopes to ensure efficient drainage.

Drainage systems are broadly categorized into surface and subsurface systems. Surface drainage systems manage runoff on the ground’s surface, employing features such as:

• Ditches and channels: Open channels that convey water to a designated outlet.
• Swales: Shallow, vegetated channels that infiltrate water while also conveying flow.
• Curbs and gutters: Guide water flow along roadways and towards inlets.

Subsurface drainage systems manage water below the ground’s surface using:

• Drains: Perforated pipes embedded in the ground, collecting subsurface water and conveying it to an outlet.
• French drains: Similar to drains, but often simpler and often use gravel for infiltration.
• Underdrains: Typically used for larger areas or agricultural settings.

The choice depends on factors like site conditions, soil type, rainfall intensity, and the desired level of drainage control. A residential lot might utilize surface drainage features, while a large industrial site might require an elaborate subsurface system.

Designing a stormwater drainage system involves several critical considerations:

• Hydrology: Accurate estimation of rainfall intensity, frequency, and duration is vital. This information is used to determine design rainfall events.
• Hydraulics: Sizing pipes and channels based on calculated flow rates to ensure adequate capacity.
• Topology: Understanding the site’s elevation and slope to route water efficiently.
• Soil characteristics: Soil type affects infiltration rates and the suitability of different drainage methods. Permeable soils allow for greater infiltration.
• Environmental regulations: Compliance with local regulations regarding stormwater management and water quality is essential.
• Cost-effectiveness: Balancing performance and cost to arrive at the most practical and economical solution.

Ignoring any of these aspects can lead to system failure, flooding, or environmental damage. For instance, not accounting for peak rainfall intensities may result in an undersized system, prone to overflowing during heavy storms.

Calculating drainage area depends on the site’s topography and boundaries. It involves:

1. Defining the drainage boundary: Identify the watershed or area that contributes runoff to a specific point. This might involve using topographic maps or surveying.
2. Measuring the area: Using appropriate tools like surveying equipment or GIS software, measure the total area within the drainage boundary. For complex shapes, dividing the area into simpler geometric figures and adding the individual areas may be necessary.
3. Accounting for impervious areas: Separately calculate the areas covered by impermeable surfaces (e.g., roads, rooftops) as these areas contribute to runoff more directly than pervious surfaces.

For example, a simple rectangular site of 100m x 50m has a drainage area of 5000 m². However, if 20% of this area is covered by an impermeable parking lot, the runoff calculation will consider this higher runoff contribution.

The drainage coefficient represents the volume of water (often in millimeters or inches) that needs to be removed from a given area in a specified time, typically 24 hours. It reflects the site’s capacity to drain water. A higher drainage coefficient indicates a greater drainage requirement. It’s crucial for designing drainage systems to handle anticipated rainfall.

For instance, a drainage coefficient of 25 mm/day signifies that the drainage system should be able to remove 25 mm of water from each square meter of the area within 24 hours. This coefficient is used in conjunction with the drainage area to determine the total volume of water the system must handle.

The importance lies in avoiding under-designing systems that fail during intense rainfall events. Properly determining the drainage coefficient considers historical rainfall data, soil type, and land use to minimize risks of flooding.

Several methods manage rainwater runoff:

• Infiltration: Encouraging water to infiltrate into the ground using techniques like porous pavements, rain gardens, and swales. This reduces runoff volume and recharges groundwater.
• Retention: Temporarily storing runoff in ponds, basins, or other storage facilities. This helps to control peak flows and reduce downstream flooding.
• Detention: Similar to retention, but the stored water is eventually released slowly. This method helps to manage the rate of runoff.
• Conveyance: Using pipes, channels, and other conveyance structures to route runoff efficiently to suitable outlets.
• Green infrastructure: Integrating natural elements like vegetated rooftops, bioswales, and permeable pavements into the drainage system to manage stormwater sustainably.

The choice of method depends on site-specific factors, such as available space, soil type, and environmental considerations. A combination of these methods is often most effective.

Soil type significantly impacts drainage system design. Permeable soils (e.g., sandy soils) allow for greater infiltration, reducing runoff volume. Impermeable soils (e.g., clay soils) require more emphasis on surface drainage systems. The design considerations include:

• Infiltration rate: Determining the soil’s ability to absorb water helps determine the effectiveness of infiltration-based solutions.
• Permeability: The ease with which water moves through the soil affects the selection of subsurface drainage systems. High permeability soils may require less extensive subsurface drainage.
• Bearing capacity: The soil’s ability to support the weight of drainage structures influences the design of pipes and other elements.

For instance, a site with clay soil necessitates a more robust surface drainage system with efficient conveyance structures to handle the greater runoff volume. A site with sandy soil may benefit more from infiltration-based techniques, reducing the need for extensive piping systems. Proper soil testing is crucial for accurate design.

Drainage system installation often faces several challenges. Common issues include improper grading leading to ponding, insufficient pipe sizing causing blockages and overflows, unsuitable pipe materials resulting in premature failure, incorrect jointing techniques leading to leaks, and inadequate consideration of future expansion or development.

• Improper Grading: Imagine a roof with a flat surface; water would pool. Similarly, incorrect land grading causes water to stagnate instead of flowing towards the drainage system.
• Pipe Sizing: Using pipes too small for the anticipated flow rate results in slow drainage and potential backups, much like trying to drain a bathtub with a tiny straw.
• Material Selection: Choosing the wrong pipe material (e.g., using PVC in highly corrosive soils) leads to early deterioration and system failure, like using the wrong type of wood for outdoor furniture.
• Jointing Issues: Poorly sealed joints allow water to infiltrate the ground, rendering the drainage ineffective and potentially causing structural damage. This is like having cracks in a dam – the water will simply bypass the structure.
• Future Considerations: Failing to account for future development or changes in rainfall patterns can overload the system and cause problems down the line, similar to designing a highway without considering future population growth.

Proper land grading is crucial for effective drainage. It involves shaping the land to create a consistent slope that directs water away from structures and towards designated drainage points. This is typically achieved by creating a gradual incline, usually between 2% and 5%, away from buildings and towards the drainage system.

To ensure proper grading:

• Conduct a topographic survey: This establishes the existing land contours and identifies high and low points.
• Design a grading plan: This plan outlines the desired slopes and the location of drainage infrastructure.
• Utilize grading tools: This includes laser levels, GPS systems, and earthmoving equipment for precise excavation and shaping.
• Regularly check grading during construction: This helps to prevent issues early on and avoid costly revisions.

For example, around a house foundation, we might establish a 1% slope for the first 10 feet, gradually increasing to 2-3% to ensure rapid water runoff.

(Note: Regulatory requirements vary significantly by region. This answer provides a generalized example, and specific requirements should be checked with local authorities.)

In many regions, drainage system installation requires adherence to building codes, environmental regulations, and local ordinances. These regulations typically cover aspects such as:

• Permitting: Obtaining necessary permits before commencing work.
• Design standards: Following guidelines for pipe sizes, materials, and installation methods.
• Erosion and sediment control: Implementing measures to minimize environmental impact during construction.
• Stormwater management: Meeting requirements for managing stormwater runoff to prevent flooding and pollution.
• Accessibility for maintenance: Ensuring easy access to the drainage system for inspection and cleaning.

Failure to comply with these regulations can result in fines, project delays, and potential legal action.

Regular maintenance is vital for the longevity and effectiveness of drainage systems. Neglecting maintenance can lead to costly repairs, system failures, and even property damage. Maintenance tasks include:

• Regular inspections: Checking for blockages, erosion, and structural damage.
• Cleaning: Removing debris such as leaves, sediment, and other obstructions from pipes and channels.
• Repairing: Addressing leaks, cracks, and other structural issues promptly.
• Vegetation control: Preventing overgrowth that can impede flow.

Think of it like regularly servicing your car; preventive maintenance is far less expensive than emergency repairs. A well-maintained drainage system minimizes the risk of water damage, protects property values, and ensures the system functions as designed for years to come.

Areas with high groundwater levels present unique drainage challenges. Standard surface drainage systems may be insufficient, and more advanced solutions are often necessary. These may include:

• Subsurface drainage systems: Installing perforated pipes surrounded by gravel or other filter media to collect and transport groundwater away from the problem area.
• French drains: A type of subsurface drainage system that utilizes a trench filled with gravel to collect and redirect groundwater.
• Sumps and pumps: Using sumps (collection pits) and pumps to remove accumulated water, particularly in basements or other low-lying areas.
• Improved soil drainage: Modifying soil properties through techniques like aeration or the addition of organic matter to improve its permeability.

The specific solution will depend on the site conditions, the extent of the problem, and the available budget. A thorough site assessment is crucial to select the most appropriate approach.

In my work, I utilize a range of software and tools for drainage design and analysis. These include:

• AutoCAD Civil 3D: For creating detailed site plans, grading designs, and generating drainage system layouts.
• HydroCAD: For hydrological modeling and hydraulic analysis of drainage systems to ensure adequate capacity and prevent flooding.
• SWMM (Storm Water Management Model): A powerful model for simulating the complex behavior of stormwater systems, including runoff, infiltration, and pollutant transport.
• GIS (Geographic Information Systems) software (e.g., ArcGIS): To integrate spatial data, such as topography and land use, into the drainage design process.

These tools allow for accurate modeling, efficient design optimization, and improved decision-making during the project lifecycle.

I have extensive experience with drainage modeling software, particularly HydroCAD and SWMM. I have utilized these tools on numerous projects to model the hydraulics of various drainage systems, from small residential developments to large-scale infrastructure projects. My experience encompasses:

• Developing hydrologic models: Defining rainfall patterns, watershed characteristics, and other relevant parameters to accurately simulate runoff.
• Building hydraulic models: Creating representations of drainage networks, including pipes, channels, and other structures.
• Calibrating and validating models: Comparing simulated results with observed data to ensure model accuracy and reliability.
• Performing sensitivity analysis: Investigating the impact of changes in various input parameters on model outputs.
• Using model results for design optimization: Adjusting design parameters, such as pipe sizes and channel slopes, to optimize system performance and minimize costs.

Through this experience, I’ve developed a strong understanding of the strengths and limitations of different modeling approaches and the ability to interpret model results effectively to make informed engineering decisions.

Assessing the capacity of existing drainage infrastructure involves a multi-faceted approach combining field investigation and computational analysis. We start by identifying the system’s components – pipes, inlets, manholes, outfalls, etc. – and their current condition. This involves visual inspections, checking for blockages, cracks, or deterioration. We then collect data on the system’s geometry (pipe diameters, slopes, lengths) and hydraulic characteristics (flow rates, water levels).

Next, we use hydrological modeling software to simulate the system’s performance under various rainfall intensities. This involves using rainfall data and applying hydrological models (e.g., Rational Method, SCS Curve Number method) to determine the peak runoff rates. We then use hydraulic modeling software (e.g., SWMM, InfoWorks) to simulate the flow through the system, determining water depths, velocities, and potential backwater effects. Comparing the modeled results with observed data (e.g., water levels during past storms) allows us to validate the model and assess the system’s capacity. If the model indicates insufficient capacity, we identify potential bottlenecks and propose upgrades.

For example, I recently assessed a drainage system in a rapidly developing suburban area. Visual inspection revealed significant sediment buildup in several manholes, restricting flow. Hydrological modeling indicated that the existing system was inadequate for projected future rainfall intensities. We recommended a combination of cleaning existing manholes, replacing undersized pipes, and adding new inlets to increase the system’s capacity.

Designing a drainage system for a large-scale development is a complex undertaking requiring meticulous planning and coordination. It begins with a comprehensive site analysis, encompassing topography, soil type, existing drainage patterns, and projected land use. We then develop a hydrological model to estimate peak runoff rates under various rainfall scenarios, considering factors like rainfall intensity, duration, and return period (e.g., 100-year storm). The chosen return period reflects the desired level of risk tolerance.

Based on the hydrological model, we design the drainage network, selecting appropriate pipe sizes, slopes, and materials to convey the runoff efficiently. The design should consider both gravity flow and possibly pumped systems for low-lying areas. We use hydraulic modeling software to simulate the flow through the system, ensuring that water depths and velocities remain within acceptable limits to prevent erosion or flooding. The design also incorporates appropriate inlets, manholes, and outfalls to manage the flow effectively. The design needs to account for future expansion and maintainability.

For example, in a recent project for a new residential development, we used a combination of swales, underground pipes, and detention ponds to manage stormwater. The swales acted as a first line of defense, slowing runoff and allowing some infiltration. The underground pipes conveyed the remaining runoff to the detention ponds, which stored excess water and gradually released it into the receiving stream, thereby reducing downstream flooding.

Integrating green infrastructure (GI) into drainage system designs is crucial for sustainable water management. GI techniques utilize natural processes to manage stormwater, reducing the burden on traditional grey infrastructure. These techniques include bioswales, rain gardens, permeable pavements, green roofs, and constructed wetlands.

Bioswales, for example, are vegetated channels designed to filter and infiltrate stormwater. Rain gardens are depressed areas planted with native vegetation that capture and absorb rainfall. Permeable pavements allow water to infiltrate the ground, reducing runoff. Green roofs provide a layer of vegetation on rooftops, absorbing rainfall and reducing the heat island effect. Constructed wetlands mimic natural wetlands, providing water treatment and habitat.

The integration process begins by identifying suitable locations for GI elements within the overall drainage design. We then design the GI elements to handle the projected runoff volumes, considering soil conditions, plant selection, and maintenance requirements. Hydraulic modeling is used to assess the effectiveness of the GI elements in reducing runoff and improving water quality. For instance, in a recent school project, we incorporated a rain garden and permeable paving in the schoolyard to reduce runoff and provide an educational opportunity for students.

My experience encompasses a wide range of drainage pipes and materials, each with its own strengths and limitations. Common materials include PVC, HDPE (high-density polyethylene), ductile iron, and concrete. PVC is cost-effective and lightweight, suitable for smaller diameter pipes. HDPE offers high strength and flexibility, useful for long spans or challenging ground conditions. Ductile iron pipes provide excellent strength and durability, suitable for high-pressure applications. Concrete pipes are durable but heavier and less flexible than other options.

The choice of material depends on factors like pipe diameter, flow rate, soil conditions, and cost. For example, in areas with aggressive soils, ductile iron or HDPE might be preferred over PVC due to their increased resistance to corrosion. In areas with high groundwater levels, pipes with high structural strength are necessary. In areas prone to earthquakes, flexible pipes such as HDPE may be beneficial to prevent damage.

I’ve also worked with various pipe joining methods, including solvent welding for PVC, electrofusion for HDPE, and mechanical joints for ductile iron and concrete. Understanding the strengths and weaknesses of different pipe materials and joining methods is critical for ensuring the long-term performance and reliability of the drainage system.

Drainage system inspections and troubleshooting are essential for maintaining optimal performance. Inspections involve a visual assessment of the system’s components, checking for blockages, leaks, cracks, or other damage. This often involves using CCTV cameras to inspect the interior of pipes, identifying problems that are not visible from the surface. We also monitor water levels and flow rates to detect any unusual patterns.

Troubleshooting involves identifying the cause of drainage problems and implementing appropriate solutions. Common problems include blockages caused by debris or tree roots, leaks in pipes, and inadequate capacity. Solutions can range from simple cleaning or repairs to more extensive replacements. For instance, I once investigated a recurring flooding issue in a commercial parking lot. CCTV inspection revealed a collapsed section of pipe. The solution involved excavating the affected area and replacing the damaged pipe section.

Regular inspections and proactive maintenance are crucial for preventing major problems and extending the lifespan of the drainage infrastructure. Early detection of problems can help prevent costly repairs and minimize disruption to the surrounding environment.

Managing drainage problems during construction requires careful planning and coordination. Temporary drainage measures are often necessary to prevent water accumulation on the construction site and protect the surrounding areas from flooding. These measures may include temporary diversions, sumps, and pumps. It’s crucial to protect existing drainage infrastructure from damage during construction activities. This often requires careful excavation techniques and the use of protective measures like shoring.

For instance, in a recent highway project, we implemented a temporary drainage system to divert runoff around the construction area. The temporary system included a series of ditches, culverts, and pumps to manage the increased runoff during construction. We also implemented measures to prevent sediment from entering the existing drainage system. A critical aspect is close monitoring of the temporary system to quickly address any issues that arise.

Effective communication between the construction team and the drainage engineer is crucial for success. Regular inspections and coordination help ensure that drainage issues are addressed promptly and efficiently, minimizing delays and potential environmental damage.

Drainage system repair and rehabilitation are essential for maintaining the long-term functionality and integrity of the infrastructure. Repair work can range from minor fixes, such as patching cracks in pipes or replacing damaged manhole covers, to more extensive repairs like replacing sections of pipe or relining damaged pipes. Rehabilitation techniques, such as cured-in-place pipe (CIPP) lining, can be used to restore the structural integrity of existing pipes without excavation.

The choice of repair or rehabilitation technique depends on the severity and extent of the damage. For minor damage, patching or spot repairs may be sufficient. For more extensive damage, pipe replacement or lining may be necessary. CIPP lining is a cost-effective and minimally disruptive method for rehabilitating damaged pipes, avoiding the need for extensive excavation. It involves inserting a resin-impregnated liner into the existing pipe, inflating it to conform to the pipe’s interior, and curing it to form a new, structurally sound pipe within the old one.

In a recent project, we used CIPP lining to rehabilitate a section of severely corroded ductile iron pipe. This method allowed us to restore the pipe’s integrity without disrupting traffic or causing extensive disruption to the surrounding environment. The use of trenchless technologies like CIPP lining is increasingly important for minimizing environmental impact and reducing construction time and costs.

Erosion and sedimentation are significant problems in drainage systems, degrading water quality and reducing the system’s effectiveness. Addressing these issues involves a multi-pronged approach focusing on prevention and remediation.

• Prevention: This involves implementing measures to reduce the velocity of water flow and stabilize the soil. Techniques include using vegetated swales (shallow, grass-lined channels) which slow water down and filter sediment, employing check dams (small barriers in channels) to trap sediment, and implementing appropriate land management practices like contour plowing to reduce runoff. Properly designed inlet structures, such as those with energy dissipators, can also minimize erosion at inlets.
• Remediation: Once erosion and sedimentation have occurred, remediation efforts are necessary. This can involve dredging channels to remove accumulated sediment, repairing eroded banks using bioengineering techniques (planting vegetation for soil stabilization), and installing riprap (rocks or other material) to protect vulnerable areas. Regular maintenance, including cleaning sediment traps and inspecting channels, is crucial for long-term success.

For example, in a project involving a steep hillside prone to erosion, we implemented a combination of vegetated swales and check dams. The swales slowed runoff, while the check dams trapped sediment before it reached the main drainage channel, substantially reducing downstream sedimentation.

Detention and retention basins are both water management tools designed to control stormwater runoff, but they differ in their primary function.

• Detention basins temporarily store stormwater runoff, allowing it to slowly release back into the drainage system. Think of it like a temporary holding tank. They reduce peak flows and minimize downstream flooding. The stored water eventually drains completely after the storm event.
• Retention basins permanently store a portion of stormwater runoff, providing water quality treatment and habitat benefits. They’re like a permanent pond. They can also reduce peak flows, but their primary purpose is long-term storage of water for infiltration or other beneficial uses.

Imagine a residential development. A detention basin would reduce the risk of flash flooding in the streets during a heavy rainstorm by temporarily storing the excess water. A retention basin might be incorporated in the development’s landscape design, providing a visually appealing feature while also improving water quality and possibly providing a habitat for wildlife.

Evaluating the environmental impact of drainage systems requires a holistic assessment considering various factors. This is often done through an Environmental Impact Assessment (EIA).

• Water Quality: We assess the impact on water quality through modeling the transport of pollutants (sediment, nutrients, heavy metals etc.) This involves monitoring water samples before and after the drainage system is implemented to track changes in pollutant concentrations.
• Habitat Impacts: We evaluate the impact on aquatic and terrestrial habitats. This might involve identifying endangered species, assessing potential habitat fragmentation, and considering the effects of altered water flow regimes.
• Greenhouse Gas Emissions: Construction and maintenance of drainage systems can produce greenhouse gas emissions. We estimate these impacts, and where possible, incorporate sustainable materials and practices to minimize the carbon footprint.
• Energy Consumption: Drainage systems may incorporate pumps or other energy-consuming elements. Energy consumption is assessed and methods for minimizing energy use are explored.

In a recent project, we conducted an EIA for a proposed highway drainage system. Our analysis showed that incorporating vegetated swales instead of traditional concrete channels would significantly reduce sediment and nutrient loading into a nearby stream and even provided some carbon sequestration.

Managing drainage in urban environments presents unique challenges due to high levels of impervious surfaces (roads, buildings, etc.), high population density, and complex infrastructure.

• Increased Runoff: Impervious surfaces prevent water from infiltrating the ground, leading to increased runoff volumes and higher peak flows.
• Combined Sewer Overflows (CSOs): In older cities, combined sewer systems carry both stormwater and wastewater. During heavy storms, these systems can overflow, releasing untreated sewage into waterways.
• Limited Space: Space constraints make it difficult to construct large-scale drainage infrastructure, requiring innovative solutions.
• Cost: Urban drainage projects are often expensive, requiring careful planning and prioritization.

For instance, in densely populated areas, we often utilize underground storage tanks or small-scale infiltration systems to manage increased runoff volumes where space for large retention ponds is limited. Addressing CSOs might involve separating stormwater and wastewater systems, a costly but necessary undertaking.

Sustainable drainage systems (SuDS) aim to mimic natural hydrological processes, reducing the impact of development on the environment. My experience involves designing and implementing various SuDS features.

• Green Roofs: These absorb rainfall, reducing runoff and mitigating the urban heat island effect.
• Rain Gardens: These depressions filled with native plants filter pollutants and reduce runoff volumes.
• Permeable Pavements: These allow water to infiltrate through the pavement, reducing runoff and recharging groundwater.
• Bioswales: These vegetated channels intercept and filter stormwater, reducing pollutant loads.

In one project, we designed a SuDS system for a new residential development. This incorporated green roofs on all buildings, rain gardens throughout the landscaped areas, and permeable pavements in parking lots. This reduced the peak discharge to the municipal drainage system by 40% and significantly improved water quality. The system also enhanced the aesthetic appeal of the development.

Ensuring the longevity and effectiveness of drainage systems requires a proactive approach encompassing design, construction, and maintenance.

• Robust Design: Drainage systems must be designed to withstand anticipated loads and environmental conditions. This includes considering factors like climate change impacts, soil conditions, and future development.
• Quality Construction: Proper construction practices are essential to ensure the system functions as intended. This includes using high-quality materials and adhering to strict quality control measures.
• Regular Maintenance: A comprehensive maintenance plan, including regular inspections, cleaning, and repairs, is vital to prevent degradation and failure. This reduces the need for costly repairs in the future.
• Adaptive Management: The system’s performance should be regularly monitored and evaluated. This allows for adjustments to maintenance and operational procedures based on observed conditions.

For instance, we use computer models to simulate the system’s performance under different scenarios, helping us anticipate and address potential issues. We also develop detailed operation and maintenance manuals for system owners to ensure long-term effectiveness.

Climate change significantly impacts drainage system design. We need to consider increased intensity and frequency of rainfall events, rising sea levels, and changes in temperature.

• Increased Rainfall Intensity: Designs must accommodate larger volumes of rainfall in shorter periods. This may involve using larger pipes, more storage capacity, and improved conveyance systems.
• Rising Sea Levels: Coastal drainage systems need to be designed to cope with higher sea levels, potentially using elevated structures or improved pump capacities.
• Changes in Temperature: Increased temperatures can lead to higher evaporation rates and changes in infiltration rates, impacting system performance. We consider this when determining storage volumes and infiltration rates in our designs.
• Extreme Weather Events: Designs should be resilient to extreme weather events like hurricanes and floods, potentially employing features like robust channel protection and flood-resistant infrastructure.

For example, in coastal areas, we’re incorporating higher freeboard (the distance between the water level and the top of a structure) in drainage structures to account for rising sea levels and storm surges. In inland areas, we’re designing systems with increased storage capacity to manage the larger rainfall volumes expected with climate change.