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2026 Vol.13, Issue 3 Preview Page
Estimation of Street Inlet Spacing on Roads Using an Improved Intercepted-Flow Equation

개선 차집 유량 산정식을 적용한 도로 빗물받이 설치 간격 산정

Jungsoo Kim1*
김 정수1*
1Associate Professor, Department of Civil Engineering, Bucheon University, Bucheon 14632, Korea
1부천대학교 부교수
*Corresponding Author
30 September 2026. pp. 169-183
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Abstract

The current Korean sewer design standard prescribes street inlet spacing only as a broad range of 10–30 m, which may lead to under- or over-design because road geometry and design rainfall are not explicitly considered. This study presents a quantitative method for determining grate inlet spacing on roads by combining an improved intercepted-flow equation, derived by the authors in a previous study from 720 half-scale hydraulic model experiments on Korean standard grate inlets (Kim et al., 2021), with an interception efficiency criterion of 95%. Here, "improved" denotes that the equation reflects the measured interception characteristics of Korean standard grates rather than theoretical formulas calibrated for foreign grate types; accordingly, the contribution of this study lies not in the equation itself but in the spacing algorithm and the design tables that couple the equation with design rainfall and a performance criterion. An iterative spacing algorithm reflecting the upgraded design frequencies of sewer conduits (10 years for lateral and 30 years for trunk sewers) was implemented as a spreadsheet-based GUI program. The program was applied to the Seoul area to produce design spacing values for three inlet sizes (40×50, 40×100, and 40×150 cm), two to four lanes, longitudinal slopes of 2–10%, gutter transverse slopes of 4% or more, and return periods of 5–30 years. The results show that inlet spacing is governed by the transverse slope, inlet size, return period, and number of lanes, in that order; the lower limit (10 m) prevails for small inlets and the upper limit (30 m) for large inlets, confirming the need to refine the current provision according to road conditions. A comparison with the allowable-spread-based framework of HEC-22 highlights the disaster-prevention-oriented nature of the proposed efficiency-based design.

Keywords
Street inlet
Interception efficiency
Intercepted flow equation
Inlet spacing

현행 하수도설계기준의 빗물받이 설치 간격 규정(10~30 m)은 도로 조건과 설계강우를 반영하지 못하는 포괄적 규정으로서 조건에 따라 과소 또는 과대 설계를 초래할 수 있다. 본 연구에서는 저자의 선행 연구에서 국내 표준형 쇠살대에 대한 1/2 축척 수리모형 실험(720회)으로부터 도출된 개선 차집 유량 산정식(Kim et al., 2021)과 과 차집효율 95% 성능 기준을 결합하여 도로 조건별 빗물받이 설치 간격을 정량적으로 산정하는 방법을 제시하였다. 상향된 관거 설계빈도(지선 10년, 간선 30년)를 반영한 반복계산 알고리즘을 스프레드시트 기반 GUI 프로그램으로 구현하고, 서울지역에 적용하여 유입부 규격(40×50, 40×100, 40×150 cm), 차선수(2~4차선), 종경사(2~10%), 횡경사(4% 이상) 및 재현기간(5~30년)별 설치 간격 설계값을 제시하였다. 산정 결과 설치 간격은 횡경사, 유입부 규격, 재현기간, 차선수의 순으로 지배되었으며, 소형 유입부는 하한(10 m), 대형 유입부는 상한(30 m)이 지배하는 조건이 광범위하게 나타나 현행 규정의 도로 조건별 세분화 필요성이 확인되었다. 아울러 미국 HEC-22의 허용 침수 폭 기반 체계와의 비교를 통하여 차집효율 기준 설계의 방재 지향적 특성을 제시하였다. 여기서 개선이란 국외 격자 형상의 실험 도표에 근거한 기존 이론식과 달리 국내 표준형 쇠살대의 실측 차집 특성을 반영하였음을 의미하며, 본 연구의 기여는 산정식 자체의 도출이 아니라 이를 설계강우 및 차집 성능 기준과 결합한 설치 간격 산정 알고리즘과 설계표의 정립에 있다.

키워드
빗물받이
차집효율
차집 유량 산정식
설치 간격
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Information
  • Publisher :Korean Society of Ecology and Infrastructure Engineering
  • Publisher(Ko) :응용생태공학회
  • Journal Title :Ecology and Resilient Infrastructure
  • Journal Title(Ko) :응용생태공학회 논문집
  • Volume : 13
  • No :3
  • Pages :169-183
  • Received Date : 2026-07-31
  • Revised Date : 2026-08-14
  • Accepted Date : 2026-08-14
  • DOI :https://doi.org/10.17820/eri.2026.13.3.169
Journal Informaiton Ecology and Resilient Infrastructure Ecology and Resilient Infrastructure
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