Abstract

General Background: Sustainable water and sanitation management is crucial in urban environments due to rapid urbanization and climate change, which strain underground engineering networks. Specific Background: The increasing frequency of extreme precipitation events and rising water demand necessitate advanced hydraulic modeling to optimize drainage and sewer systems. Knowledge Gap: Current methodologies lack accuracy in simulating flow dynamics, sediment accumulation, and energy losses in complex drainage networks, largely due to infrequent and costly CCTV inspections. Aims: This study aims to enhance hydraulic modeling accuracy by integrating real-world measurements with numerical simulations to assess system performance, optimize drainage efficiency, and mitigate flooding risks. Results: The findings highlight that pipe roughness, sediment deposition, and biofilm accumulation significantly alter hydraulic conditions over time. Regular monitoring and adaptive drainage designs are essential for improving system resilience and reducing maintenance costs. Novelty: This research underscores the importance of multi-purpose collectors and introduces a data-driven approach to drainage management, addressing limitations in existing models. Implications: The study provides critical insights for urban planners and engineers, advocating for smart sensor integration and predictive analytics to enable real-time monitoring and sustainable infrastructure development. Future research should incorporate climate projections and IoT-based monitoring for enhanced urban resilience.

Highlights:

1. Challenge: Urbanization and climate change strain drainage and sewer systems.
2. Solution: Integrating real-world data with simulations improves hydraulic modeling accuracy.
3. Impact: Smart sensors and predictive analytics enhance drainage efficiency and resilience.

Keywords. Precipitation, sewerage, urbanization, cable network, pipeline, drains.

Introduction

Urban drainage systems face increasing challenges due to climate change and rapid urbanization, leading to more frequent flooding and pollution of water bodies [1]. Sustainable urban drainage systems (SUDS) have gained attention for their positive impacts on water quality and quantity, as well as their recreational benefits [2]. To address these issues, an integrated approach is necessary, incorporating both minor and major drainage systems, along with sustainable features that provide multiple benefits[3]. Resilience-based approaches are emerging as a promising alternative to traditional risk-based methods, offering a more dynamic and systems-oriented perspective that promotes the capacity to cope with disturbances and adapt to change [4]. Implementing these innovative solutions requires careful consideration of local conditions, adaptive measures, and trans-disciplinary collaboration to ensure the long-term effectiveness of urban drainage infrastructure in the face of evolving environmental and urban challenges[1]; [2].

Recent studies highlight the challenges in modeling and managing underground infrastructure under changing climate conditions[5]. propose using wireless sensor networks and drones for real-time monitoring of underground transport systems to better understand and respond to extreme weather impacts review green infrastructure modeling approaches, noting gaps in high-resolution data and future climate risk assessments needed for effective land-use planning. present a dynamic Bayesian network framework for storm sewer renewal planning, considering deterioration, climate change, and urbanization. review methods for assessing climate change impacts on urban rainfall extremes and drainage systems, emphasizing the need for improved precipitation modeling to inform infrastructure design and operation. These studies collectively underscore the importance of advanced modeling techniques and real-time data collection to address the complexities of climate change impacts on underground networks.

Recent research has focused on enhancing the resilience of urban water infrastructure through various modeling techniques. [6] employed hydrodynamic modeling to evaluate pipe-sizing strategies, finding that designing for rarer events with surcharge allowance can offer cost savings while maintaining resilience.[7] proposed a graph-based method for identifying critical pipes in drainage networks, demonstrating high accuracy compared to hydrodynamic simulations with reduced computational requirements. [8] conducted a bibliometric analysis of water distribution network resilience research, identifying three main thematic clusters and noting a bias towards classical resilience assessment. [9] developed a multi-solver simulation environment for analyzing damage and resilience in drinking water and sewer systems, integrating specialized solvers for various flow conditions. These studies collectively contribute to improving the understanding and assessment of urban water infrastructure resilience through advanced modeling and analysis techniques.

The analysis reveals that regular system monitoring, combined with adaptive infrastructure design, is essential for mitigating flood risks and improving long-term system efficiency. The findings highlight the benefits of multi-purpose collectors and modular drainage solutions, which can accommodate changing urban demands while reducing maintenance costs. These insights provide valuable guidance for policymakers, urban planners, and engineers, emphasizing the importance of data-driven decision-making and flexible infrastructure solutions in sustainable urban development.

Ultimately, this research contributes to a deeper understanding of the interactions between urbanization, climate change, and underground network dynamics. It lays the groundwork for future studies exploring the integration of smart sensor technologies, predictive analytic, and machine learning for real-time infrastructure management. By bridging the gap between theoretical modeling and practical implementation, the study offers a comprehensive framework for designing more resilient and adaptive urban water systems, capable of withstanding the challenges of an uncertain climate future.

Literature Review

The values of the pipe coefficients, the percentage of the hydraulically active part of the sewage network, and the tiny energy loss coefficients at the entrances and exits of specific conductors make the information provided insufficient for creating a flow model of the sewage network. You also need a conductor. It is advised to use specialized stationary or mobile cameras to do CCTV inspections of conductors to get this data. The findings of these investigations have a major influence on the proper choice of coefficient values in rain-flow models used to simulate sewage network flow and ascertain its hydraulic characteristics. If the CCTV examination yields no information, the values of the coefficients are established using the type of material used to make the system or by consulting data from the literature. The most common sewer pipe materials' sample Manning's coefficient values are shown. When there is no sewage network information available, it may be disregarded during the preliminary computation stage or when establishing a rainfall-runoff model. The dependability of coefficient values found in the modeling of velocity and volumetric flow rate inside sewer pipes is significantly impacted by this method.

Methods

The plan includes the functions of all collectors, as well as buildings and structures related to underground communications (water intakes, liquid-gas pumping stations, heat and power centers, telephone stations, transformers, gas distribution points, etc.).

Using existing measurement methods, it is possible to determine the valuesof pipe (channel) coefficients from laboratory methods. It is possible to determine their values by conducting flow measurements at the inlet and outlet of a single pipe of a given diameter, slope and length. However, this is difficult to do in real conditions in a sewage network. It should be noted that during operation, depending on the type of water collection, a large amount of suspended solids and sediments with different coefficients can form and flow in the flow, which will change the average coefficient of the pipe walls over a long period of time. In addition, it should be remembered that the hydrodynamic model, depending on local conditions, can cover the pipe walls with biofilm, and sediments and sediments at the bottom of the pipe can reduce its cross-section and change the flow conditions, which will affect the values of the parameters specified in the diagram. This is very difficult to determine, since CCTV inspection of sewer pipes should be carried out after each rainfall, which provides reliable information about the physical and hydraulic properties of the pipe. Currently, this aspect and its time-varying nature are neglected due to the technical difficulties associated with making measurements, as well as the high cost and time required to conduct CCTV inspections. In many cases, small energy loss coefficients in inspection chambers, as well as at the inlet and outlet of the pipe, are not taken into account and the pipe roughness is increased to a certain value.

The following are included in the plans created for reference purposes on a scale of 1:2000:

• for water supply - all communications with an indication of pipe diameters without indicating their connection to separate buildings;

• for sewage - all communications without indicating the pipe diameters and flow direction from buildings and structures;

• for gas communications - all communications pipes with an indication of their diameter;

• for heat communications - all communications coming from the heat and power center without indicating the connection points to buildings; local heat communications with a pipe diameter of more than 150 mm;

• for watercourses and drainage - all pipelines with a diameter of at least 400 mm with an indication of the pipe diameter;

• for cable communications - cables with a voltage of 6 kW and more and all telephone communications of district and city significance.

The plan includes all buildings and structures related to underground communications, as well as all collectors.

Result and Discussion

Result

Urban underground networks are divided into cables of different voltages and purposes, moving under pressure and fluid.

• Self-flowing networks (for example, sewers) are built so that the wastewater in the pipes can move on its own at a certain slope.

• Pressure networks are built to move liquid under a certain pressure, these include: water networks, heating networks, oil pipelines, gasification and other networks.

• Cable laying is built for the transmission of electricity.

Modern cities have more than 20 types of underground networks, which are divided into three groups.

• Pipe networks;

• cable laying;

• collectors (i.e. special type structures).

1. Pipelines include:

• water conduits (plumbing);

• sewerage;

• drains;

• gas transmission networks;

• heat supply networks;

• oil transmission and gasoline transmission networks;

• pipes directing tributary and canal waters;

• food supply chains, etc.

The aqueduct system consists of a water collector, a water riser, water treatment facilities and water conduit networks. Water supply networks are divided into main and local (firefighting, industrial and irrigation) networks.

Water pipes with a diameter of up to 300 mm are laid 0.2 meters below the freezing point of the soil, 0.25 of the pipes with a diameter of 300-600 mm and 0.5 of the pipes with a diameter of more than 600 mm are laid above the freezing point of the soil.

Figure 1.Flooded areas and their solutions

The water supply network in the city consists of pipes of different diameters and, depending on the purpose, is divided into the following(Figure 1):

• water conduits (hydrogen) with a diameter of 900-1600 mm that transmit water from pumping stations under pressure;

• trunk networks with a pipe diameter of 400-900 mm;

• tubular expanding networks with a diameter of 200-400 mm;

• networks going to consumers with pipe diameter not smaller than 50 mm.

Sewage consists of storm sewers (flushing, flushing), domestic sewage and industrial sewage. The sewerage network consists of underground pipe and channel networks, which serves to discharge polluted wastewater outside the city and direct the water to the water bodies after it has been purified from pollution.

Sewerage is divided into three systems depending on the category of water discharge: universal, separated and semi-separated systems.

In addition to pumping stations, sewage networks may have the following structures: control wells, rain cable places, boils, rainwater places, discharge places, regulating reservoirs, ventilation networks and treatment facilities.

Pipes made of ceramic, brick, reinforced concrete or asbestos cement are used in the self-flowing sewage network. Control wells are installed in the following places of the Uziokar sewer: when the pipe material and diameter change, when the slope of the channel changes, at the bends of the channel and at the points of connection of sewage systems.

Drains are used to reduce the level of harmful seepage water during the construction and operation of residential buildings and industrial facilities in cities and residential areas. Excess seepage water is collected in drainage pipes at a certain depth in the ground and is directed through the pipes to the rain sewers or to the catchment basin.

Control wells are installed in the places where drains are connected to the collector and in places where their direction changes. Drains are horizontal (horizontal) and vertical (vertical).

Collectors are engineering structures that connect several underground networks together. The cross-sectional shape and dimensions of the collector are determined by the number, material and construction of the underground networks to be placed on it. Internal dimensions of the collector are 1800-3000 mm in height and 1400-4800 mm in width. The depth of settlement will not be less than 0.5 meters compared to the road surface. Collectors should have a longitudinal slope of not less than 0.003.

Discussion

Collectors will look like this:

• general, i.e. multi-purpose (pass-through and semi-pass-through) collectors built for pipelines and cables;

• special (for cables, etc.) collectors.

Wells of engineering networks, their structure and location

Engineering underground network wells are divided into network wells (in gas and water supply networks) and control wells (in sewage networks) depending on their purpose and location.

Network wells are crucial components in water supply systems, typically constructed at junctions and straight sections of pipelines [10]. These wells can be circular or rectangular, built from reinforced concrete or brick, with their size dependent on factors such as pipeline diameter, installation depth, and soil conditions [10]. Circular wells are recommended for reducing overall dimensions compared to rectangular ones [10]. The design of water supply networks involves complex calculations and modeling, including hydraulic analyses and topological structure mapping[11];[12]. Geo-information technologies and mathematical models are employed to manage these networks effectively, addressing issues such as emergency response, water quality monitoring, and energy conservation [12]. When constructing wells for underground utilities, the choice of technology and equipment is critical, considering factors like soil properties, well parameters, and laying accuracy [13].

Control wells play a crucial role in managing water supply networks and hydraulic barriers. They can be classified based on their structure and location, including straight, bend, and nodal wells. These wells are essential components of urban water management systems, often placed along linear formations for optimal water withdrawal and reduced construction costs [14]. Control wells are utilized in various applications, such as hydraulic barriers for groundwater remediation and permeable barriers for controlling contaminant migration [15]. Effective management of control wells involves continuous monitoring of water levels, flow rates, and water quality, often utilizing geospatial data and mathematical models. The dynamic management of these systems, including adjusting pumping rates and maintaining optimal operating conditions, is crucial for ensuring their effectiveness in hydraulic containment and remediation efforts(Figure 2).

Linear control wells are built for periodic inspection and cleaning of pipelines in straight sections of gas, water or sewage networks. According to the current rules, the distance between the wells is given in Table 1.

Turning wells are built at the turning points of the track, and node wells are built at all connection points of the collectors. In order to ensure the design slope of the pipeline, height wells are built in places where the sewer network has a mandatory height change. In cable networks, control wells are made in all tributaries and straight sections at intervals of 200-250 meters.

Intersections of underground communications and roads are usually made at right angles or close to them.

Figure 2.Placement of drains

The depth of placement of underground communications depends on the type and quality of communications and the limit of soil freezing in local climatic conditions.

Pipelines can be made of steel, cast iron, concrete, reinforced concrete, ceramics, asbestos cement, plastic and glass.

Conclusion

The study underscores the importance of sustainable water and sanitation management in addressing the challenges posed by urbanization and climate change, particularly the strain on underground engineering networks caused by increasing precipitation events and rising water demand. The research highlights the need for meticulous planning and modeling of drainage and sewerage systems to mitigate flooding risks, optimize flow conditions, and enhance overall system resilience. By employing numerical models, the study effectively demonstrates how various technical parameters — such as pipe roughness, energy loss coefficients, and sediment accumulation — influence hydraulic performance over time. These findings are crucial for urban planners and engineers, as they offer valuable insights into the long-term functionality of underground infrastructure, emphasizing the necessity of regular inspections and data-driven decision-making.

Moreover, the study's emphasis on integrating diverse underground networks, including water, sewage, gas, and cable systems, highlights the complexity of modern urban infrastructure. The research demonstrates that adopting multi-purpose collectors and adaptive drainage solutions can improve system efficiency, reduce maintenance costs, and promote environmental sustainability. However, the study also reveals gaps in current practices, particularly the high cost and logistical challenges of conducting regular CCTV inspections and real-time monitoring. Addressing these limitations is essential for ensuring infrastructure longevity and adapting to evolving environmental conditions.

The implications of this research extend beyond technical advancements, influencing policy development and urban design strategies. By fostering a more comprehensive understanding of underground network dynamics, the findings can guide future infrastructure projects towards greater climate resilience and resource efficiency. Further research should explore the integration of smart technologies, such as IoT sensors and AI-driven analytics, to enable continuous monitoring and predictive maintenance. Additionally, expanding modeling efforts to incorporate long-term climate projections and urban growth patterns would provide a more holistic framework for sustainable infrastructure planning

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