هدررفت آب از شبکه های آبرسانی شهری و عوامل مؤثر بر آن
محورهای موضوعی : مدیریت بهره برداری از سامانه های آبی
1 - گروه مهندسی عمران آب و سازه‌های هیدرولیکی، دانشکده عمران و محیط زیست، دانشگاه تربیت مدرس، تهران، ایران.
کلید واژه: مدیریت نشت, دبی نشت, شبکه آب¬رسانی, فشار, ترک,
چکیده مقاله :
هدررفت آب سالانه خسارات بسیاری به منابع آب، زیرساخت¬های عمرانی، محیط¬زیست و شرکت¬های توزیع آب وارد می¬کند. هدررفت آب از شبکه¬های آبرسانی شهری، به¬ویژه در مناطقی که منابع آب کمیاب هستند، یک مسئله مهم است. نشت از سامانه¬¬های آبرسانی شهری که بخشی از هدررفت آب را تشکیل می¬دهد، بخش عمده¬ای از آن را در بر می¬گیرد. این موضوع به دلایل بسیاری چون قدیمی شدن شبکه آبرسانی، آسیب رسیدن به لوله¬ها به دلیل تنش¬های سربار خاک و ترافیک شهری و همچنین افت و خیز فشار شبکه آبرسانی، اجرای نادرست لوله¬کشی شهری و خاکریز نامناسب است. با بررسی مؤلفه¬های تأثیرگذار در دبی نشت مثل فشار، جنس لوله، محیط خاکی پیرامون لوله و دما، می¬توان میزان رخداد نشت را کاهش داد و حجم نشتی را مدیریت کرد. با بررسی¬های آزمایشگاهی و میدانی انجام شده بر خلاف رابطه¬ی روزنه فشار-نشت، توان نشت در بازه¬ی 5/0 تا 79/2 قرارگرفته و بیشتر از 5/0 است که تفاوت در جنس لوله، تفاوت ابعاد و نوع ترک در تغییر توان در بازه¬ی گفته شده مؤثر است. با انتخاب مناسب دانه¬بندی خاک پیرامون لوله و کاهش D50 خاک می¬توان دبی نشت را کاهش داد. در مقاله¬ی حاضر ابتدا كلیاتی از هدررفت آب، انواع آن و دلایل آن مطرح می¬شود سپس به مبانی محاسبه¬ی نشت پرداخته می¬شود.
Water loss is a significant issue that leads to substantial damage to water resources, civil infrastructure, the environment, and water distribution companies. Urban water supply networks, particularly in regions with scarce water resources, face challenges related to water loss. Leakage from these networks constitutes a major portion of the overall water loss. Factors contributing to leakage include the aging of water supply systems, pipe damage due to soil stresses and urban traffic, fluctuations in water pressure, improper urban plumbing practices, and inadequate embankments. Examining factors such as pressure, pipe type, soil environment, and temperature can help identify the causes of leakage and effectively manage and mitigate its volume. Laboratory and field investigations have revealed that the leakage power, contrary to the pressure-leakage relationship, falls within the range of 0.5 to 2.79, with values exceeding 0.5 due to variations in pipe types, dimensions, and the type of cracks. Reducing the D50 (median grain size) of the soil and selecting an appropriate soil granulation around the pipes can effectively reduce the leakage flow rate. This article provides an overview of water wastage, its types, and underlying causes, followed by a discussion on the fundamentals of leakage calculation.
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