기후변화 대응을 위한 홍수위험평가 및 홍수방어기준 전략 마련 연구(Ⅰ)

Title
기후변화 대응을 위한 홍수위험평가 및 홍수방어기준 전략 마련 연구(Ⅰ)
Authors
정기철
Co-Author
이문환; 한대호; 정아영; 유종현
Issue Date
2022-12-31
Publisher
한국환경연구원
Series/Report No.
기후환경정책연구 : 2022-03
Page
136 p.
URI
https://repository.kei.re.kr/handle/2017.oak/23922
Language
한국어
Keywords
차등적 홍수방어목표, 연평균 기대피해액, 홍수방어기준 개선, 정량적 홍수위험 분석, 기후변화를 고려한 홍수방어계획, Differentiated Flood Defense Level, Expected Annual Damage, Improvement of Flood Defense Criteria, Quantitative Flood Risk Analysis, Flood Defense Plans Considering Climate Change
Abstract
Ⅰ. 서론 1. 기후변화와 홍수재해 ㅇ기상청(2015) 보고서에 따르면 지구 표면 온도는 21세기 전반에 걸쳐 상승할 것이며, 폭염뿐만 아니라 극한강수현상의 발생빈도와 강도 또한 늘어날 가능성이 큰 것으로 전망하고 있음 ㅇ기온변화에 따른 강수량 증가는 온실가스 배출 정도에 따라 3~14%로 전망되었으며, 미래 전반기(2021~2040년)보다 미래 후반기(2081~2100년)에 큰 폭으로 늘어날 것으로 보여, 홍수와 같은 재해 피해가 지속해서 증가할 것으로 예측됨 ㅇ국내 기상측정지점에서 수집한 자료에서는 모두 1900년 초반부터 최근으로 올수록 집중호우의 발생 횟수가 증가하는 추세로 나타나고 있으며, 단기간의 국지적 집중호우 발생으로 홍수피해 규모가 커질 것을 예상할 수 있음 ㅇ최근 10년(2011~2020년) 동안 호우로 인한 인명피해는 139명, 태풍으로 인한 피해 포함 시 182명이며, 총 피해액은 호우피해가 2조 1,557억 원, 태풍 포함 시 4조 1,126억 원으로 집계되는 등 홍수로 인한 피해가 지속적임 2. 연구의 필요성 및 목적 ? 연구의 필요성 ㅇ국내 하천 홍수방어목표는 하천등급 기준으로 나누어져 있지만, 홍수방어의 최종목적이 지역사회 침수피해의 사전 방지라는 점을 고려할 때, 주변 여건을 고려해 피해 저감에 초점을 맞추며 정량적 영향평가 기반의 홍수방어목표 설정이 필요함 ㅇ?물관리기본법? 제27조에 의거, 분야별 물관리 계획을 아우르는 국가 최상위 계획인 ??제1차 국가물관리기본계획(2021-2030)??이 발표되었고, 분야별 전략과제 중 물재해 안전체계 구축에 대한 전략을 제시하여 물재해, 특히 기후변화에 따른 홍수대응체계 구축 및 침수관리체계 강화의 필요성을 강조하고 있음 ㅇ물관리 일원화 이후 ?하천법?과 ?수자원법?이 환경부로 이관되었고, ?하천법?에 의거한 ??하천기본계획??, ?수자원법?의 ??하천유역수자원관리계획??을 기반으로 홍수방어 및 치수계획을 수립하고 있으며, 환경부 소관 법령인 ?물관리기본법?을 토대로 ??국가물관리기본계획???, ??유역물관리종합계획??을 수립하는 등 홍수와 같은 물재해 경감과 물관리 취약성 대응방안을 지속적으로 마련하고 있음 ? 연구목적 ㅇ홍수 빈도별 피해액에 기반한 정량적 홍수위험분석, 기후변화와 함께 사회·경제 변화도 고려한 홍수위험도 기준 설정을 통해, 기후변화 영향·취약성 평가도구 개발, 위험을 반영한 기후변화 적응체계 구축 등 실효성 있는 기후변화 적응 정책 기반을 마련하고자 함 ㅇ지역별·하천별 홍수사상에 따라 예상되는 침수피해액 산정방법을 마련하고 사례분석을 수행하여, 하천별 연평균 예상 피해액을 현재 홍수방어목표와 비교분석하고, 대규모 침수피해가 예상되는 하천을 선별하고, 홍수방어목표 강화 및 차등화 필요성을 검토하여 정책적 시사점을 도출하는 것을 목적으로 함 3. 연구내용 및 범위 ? 연구내용 ㅇ본 연구에서는 홍수피해에 대한 경제성 분석을 통해 기후변화를 고려한 홍수방어기준 개선, 관련 법령 및 치수계획 정비 방향을 논의하고자 함 ㅇ환경부에서 제공하는 홍수위험지도 빈도별 홍수위험 정보를 활용하여 침수범위 및 침수심에 대한 피해액을 산정하고, 홍수재해 취약성 평가로 홍수피해 정도를 검토함 ㅇ2022년 기준 시행 중인 부처별 홍수방어 법령 및 계획 현황을 조사하고, 그 변화에서 나타나는 시사점을 분석하여, 선택적·차등적 홍수방어목표 정립을 제안함 ? 연구범위 ㅇ1차 연도의 주 연구범위는 낙동강권역 지방하천을 중심으로 홍수 빈도별 예상되는 인명·재산 피해에 대한 경제적 리스크 정량화 방안, 하천별 침수피해액 추정 및 취약성을 검토하는 것이며, 2차 연도의 주 연구범위는 기후변화 및 사회·경제 발전 시나리오를 고려한 정량적 홍수위험 분석 기반 홍수방어기준과 차등화 된 홍수방어목표, 즉 탄력적 홍수대응방안 제시임 ㅇ1, 2차 연도 연구를 통해 기후, 사회·경제 여건을 반영한 홍수재해 리스크 정량화 분석, 다양한 시나리오별 분석을 기반으로 기후변화 적응정책의 비용 효과를 알아볼 수 있는 정책지원도구를 제시하고자 하며, 본 연구는 홍수방어에 필요한 비용 추정, 방어를 위한 대안 검토는 포함하지 않음 4. 연구 관련 개념 정의 ㅇ정량적 홍수위험 분석은 홍수손실과 위험자산의 가치를 평가한 결과를 보여주는 것으로, 원치 않는 홍수재해로 인한 위험을 계량적 가능한(금전적) 형태로 정의함 ㅇ본 연구에서 사용한 홍수방어 관련 주요 용어는 다음과 같음 -연평균 기대피해액(Expected Annual Damage) 또는 연평균 예상피해액: 홍수로 인한 침수피해액을 지칭하며, 빈도별로 계산한 피해액을 빈도별 연간 생기확률과 곱하여 누계한 금액 -홍수피해액지도(Flood Damage Map): 추산한 연평균 기대피해액을 시각적으로 표현한 지도 -홍수방어기준(Flood Defense Criteria): 홍수로 인한 상습침수지역이나 재해위험도가 높은 지역에 대하여 침수피해를 방지하기 위해 정한 기준 -취약성 분석(Vulnerability Analysis): 하천별·지역별 인구, 산업, 주택 및 건축물, 공공시설, 농경지 등의 현황 및 장래 예측을 기반으로 한, 홍수의 잠재적 위험 분석을 뜻함 Ⅱ. 국내 홍수방어법령 및 계획 1. 물관리기본법 및 국가물관리기본계획 ㅇ?물관리기본법?에는 홍수방어와 관련된 구체적 조항은 없으나 물관리 기본원칙으로 유역별 관리를 제시하고 있으며, 홍수로 발생하는 재해 예방 및 관련 계획 수립에 대한 사항을 규정하고 있음 ㅇ??국가물관리기본계획??에서는 기존 시설 중심, 과거 기상여건만 고려한 하천등급 위주의 획일적 관리에서, 기후변화에 따른 미래 불확실성, 예상 피해지역 및 규모 등을 고려하는 선택적 집중 관리로 관리방향을 전환할 것을 제안하고, 기후변화 및 사회·경제적 중요도를 반영한 홍수방어목표 수립을 추진과제로 명시하고 있음 2. 하천법·수자원법 및 관련 계획 ㅇ홍수방어와 관련하여 ?하천법?에서는 홍수피해를 예방하기 위한 하천의 지정·관리·사용 및 보전 등에 관한 사항을 규정하고 있으며, 관련 계획인 제25조 ??하천기본계획??을 통해 하천의 홍수방어기준 및 목표를 정하고 있음 ㅇ?수자원법?에서는 물 관련 재해의 경감·예방을 위하여 수자원의 조사, 수자원계획의 수립·집행 및 수자원 관리의 효율화에 필요한 사항을 규정하며, 관련 계획으로는 제17조 ??수자원장기종합계획???(2021년 이후 더는 수립되지 않음), 제18조 ??하천유역수자원관리계획??, 제19조 ??지역수자원관리계획??, 제20조 ??특정유역치수계획??이 있음 3. 재난 및 안전관리 기본법 및 관련 계획 ㅇ?재난안전법?은 각종 재난으로부터 국토를 보존하고 국민의 생명·신체 및 재산을 보호하기 위하여 국가와 지방자치단체의 재난 및 안전관리체계를 확립하며, 재난의 예방·대비·대응·복구와 그 밖의 안전관리에 필요한 사항을 규정하는 것을 목적으로 함 ㅇ?재난안전법?은 재난관리를 위한 기본법 성격을 띠는 법령이지만 홍수방어와 관련된 구체적 규정은 포함하고 있지 않으며, 관련 계획인 ??국가안전관리기본계획??, ???시·도안전관리계획??, ??시·군·구안전관리계획??과 함께 ??기능연속성계획??, ??재난대응활동계획?? 등 각종 예방·대비·대응·복구 관련 계획에 대한 규정을 포함하고 있음 4. 자연재해대책법 및 관련 계획 ㅇ?자연재해대책법?에서는 풍수해 전반에 대한 정책을 규정하고 있으며, 하천 유량 증가로 인해 발생하는 홍수방어와 관련해서는 ‘지구단위 홍수방어기준’이 있음 ㅇ홍수, 호우로 발생하는 재해를 예방하기 위한 정책목표를 ‘강우량’ 값으로 제시하는 ‘방재성능목표’에 대한 규정을 포함하고 있으며, 관련 계획으로는 ??풍수해 생활권 종합계획??, ??자연재해저감 종합계획??이 있음 5. 국토계획법 및 관련 계획 ㅇ?하천법?과 ?수자원법?이 환경부로 이관되면서, 국토교통부에는 홍수방어기준 및 목표와 직접적인 관련이 있는 법령은 없음 ㅇ다만 하천 주변 제내지의 재해취약성을 평가하여 도시계획에 반영하기 위해 2015년 6월 ?국토계획법?에 재해취약성 분석을 신설한 바 있으며, 관련 계획으로는 ??도시·군 관리계획???이 있음 6. 시사점 ㅇ물관리 일원화, ?물관리기본법? 제정, ??국가물관리기본계획??의 수립 등 정부 물관리 조직 및 국가 최상위 법·계획의 전반적인 변화가 진행되고 있고, ??국가물관리기본계획??에서도 하위 및 관련 법령과 계획의 개선 필요성에 대해 논의하고 있음 ㅇ기후변화를 고려한 홍수방어기준 및 목표를 기본방향으로 설정하기 위해서는, 관련 법령·계획에 대한 검토, 세부기준을 결정하기 위한 정량화된 분석 및 방법론의 구체화, 효율적인 홍수방어계획을 수립하기 위한 계획 평가체계 구축이 필요함 Ⅲ. 국내 홍수피해비용 산정 연구사례 1. 간편법 ㅇ1993년 건설부 하천시설기준에서, 농작물 피해액을 산정한 뒤 계수를 곱하여 다른 피해항목을 결정하는 방식인 간편법이 처음으로 사용되었음 ㅇ간편법이 개발된 시기에는 국내 홍수피해의 상당 부분이 농업자산에 집중되었으며, 상세한 추정은 가용자료와 기술면에서 한계가 있었음 2. 개선법 ㅇ2001년 하천정비사업을 대상으로 한 “치수사업 경제성 분석 개선방안 연구”가 수행되면서, 침수면적을 변수로 하는 회귀식에 기반해 홍수피해를 산정하는 개선법이 제안됨 ㅇ하천 범람 피해액에 가장 큰 영향을 미치는 요소로 강우량과 침수면적을 강조하면서, 이들의 상관관계를 도시 규모 및 유형에 따라 대도시, 중소도시, 전원도시, 농촌지역, 산간지역의 5개 유형으로 구분하여 분석함 3. 다차원법 ㅇ대상 지역의 자산 규모 및 공간적 분포와 관련된, 각종 통계 및 공간자료를 지리정보시스템을 이용하여 분석하는 다차원법이 2004년 개발되어 실무에 활용되고 있음 ㅇ다차원법에서는 주거용지 면적을 기반으로 계산한 침수편입률을 사전 결정된 행정구역의 자산분석 결과와 곱해 실제 피해를 본 구역의 자산가치를 결정함 4. 객체기반법 ㅇ최근에는 다차원법에서 제기되어 온 문제점을 개선하고자, 해상도가 높은 자산데이터(인벤토리) 및 국내 실정의 손상함수를 활용한 객체기반법의 활용이 대두되고 있음 ㅇ객체기반법은 지역별 평균값을 사용해 개별 건물 및 자산의 공간특성을 무시하는 다차원법에 비해, 공간데이터를 기반으로 고해상도의 공간단위 분석을 실시하기 때문에 실제 피해액과의 오차를 크게 감소시킬 수 있음 5. 시사점 ㅇ현재 사용되고 있는 다차원법은 침수구역을 식별하고, 이 구역이 속한 행정구역의 평균 자산 데이터를 이용해 홍수피해액을 추정하고 있어, 개별 자산의 공간특성을 고려하지 않기 때문에 실제 피해액과의 오차가 큰 단점이 있음 ㅇ객체기반법에서는 고해상도 데이터 기반 공간 단위 분석을 시행하므로 실제 피해액과의 오차를 감소시킬 수 있음 ㅇ본 연구에서는 GIS 기반 공간데이터를 이용해 100m 격자 단위로 분석을 시행하여 홍수 침수피해액 산정의 신뢰성 및 정확성을 향상하고자 하였음 Ⅳ. 홍수위험지도 및 공간인벤토리 자료 구축 1. 홍수위험지도 개요 ? 홍수위험지도 정의 ㅇ비구조물 관련 홍수방어대책은 홍수방어 및 조절을 위한 시설물 축조 제외와 홍수피해를 제거하거나 경감시키기 위한 제반 활동을 의미하며, 홍수범위 및 피해 경감을 위한 포괄적 홍수관리라 할 수 있음 ㅇ홍수위험지도는 과거 구조물 관련 대책에 집중됐던 우리나라 치수정책의 한계를 극복하기 위한 비구조물적 대책의 일환으로, 홍수 발생 이해와 그 영향 범위 파악에 가장 기초가 되는 정보를 제공하며, 홍수경감대책 수립, 홍수피해 사전 대비, 예방 및 복구 등 홍수관리의 전 과정에 걸쳐 활용할 수 있음 ㅇ홍수위험지도는 홍수방어계획 수립을 위한 구조물적·비구조물 관련 대책 수립 모두를 지원하는, 하천공간정보 기초자료 관리를 위한 특수목적지도로 볼 수 있음 ? 우리나라 홍수위험지도 도입 배경과 작성 경위 ㅇ도입 초기 지도는 ‘홍수지도’라 명명하였으나, 2007년 ?하천법? 개정에 따른 최초 법제화 이후 ‘홍수위험지도’로 운용하고 있으며, 하천 범람으로 인한 침수범위 및 깊이 등 예측에 대한 중심에서 하천의 범람에 의한 홍수위험지도와, 설계 시 예상 강우량 초과로 인한 내수침수피해를 예측하는 내수침수위험지도를 모두 포함하고 있음 ㅇ홍수위험지도의 현재 법적 정의는 ?수자원법? 제7조에 따라 “홍수피해의 위험도를 예측하는 지도”이며, ?자연재해대책법? 제21조는 침수흔적도, 침수예상도, 재해정보지도를 재해지도로 정의하고 있음 ? 우리나라 홍수위험지도 작성에 관한 기준 ㅇ하천 범람으로 인한 홍수위험지도의 공간적 범위는 대상 하천과 그 지류에서 가상의 홍수로 발생할 수 있는 범람원을 모두 포함하는 구역이며, 내수침수위험지도의 공간적 범위는 해당 전체 배수구역에서 설계강우량을 초과하는 강우 발생, 외수위 상승, 펌프장 고장 등 가상의 상황으로 내수침수 피해가 발생할 수 있는 구역임 ㅇ홍수로 인한 제내지의 가상 침수 상황을 모의로 실험하려면 먼저 범람 발생 조건을 가정해야 하며, 홍수시나리오는 유역조건, 홍수규모(내수의 경우 강우 규모), 홍수범람(내수의 경우 내수침수) 등 세 가지로 구분함 2. 공간인벤토리 개요 ? 공간인벤토리 구축을 위한 범위 및 방법 ㅇ본 연구에서는 건설교통부(2001)와 한국개발연구원(2008) 방식을 따라 연평균 기대피해액을 추정했으며, 객체기반법 및 GIS 기반 공간데이터를 적극적으로 활용하여 연평균 기대피해액 추정치 신뢰도 및 정확도를 높이도록 하였음 ㅇ선행연구와 비교해 가장 큰 차별점은 피해액을 시·군·구 혹은 읍·면·동과 같은 행정구역 단위가 아닌, 100m2 크기(100m×100m)로 구획한 고해상도 공간단위별로 산정한 것과, 낙동강권역 468만여 곳의 모든 공간별로 연평균 기대피해액을 평가한 것임 ㅇ낙동강권역 지방하천 798곳의 자료를 50년, 80년, 100년, 200년 단위로 분석하였으며, 통계분석은 자료 확보가 가능한 2019년을 기준으로 함 ? 피해항목별 홍수 침수피해액(연평균 기대피해액) 산정방법 ㅇ1차 연도 연구에서 홍수피해는 데이터 구득 및 체계적인 산정방법 부재를 고려하여 피해 항목 4종류, 즉 주거자산, 농업자산, 산업자산, 인명을 중심으로 분석하였음 ㅇ주거자산, 농업자산, 산업자산 등 일반자산은 지역별 자산 데이터를 구축하고, 이를 바탕으로 침수 발생 시 예상되는 연평균 피해액의 기댓값을 기반으로 하는 연평균 기대피해액을 산정하였으며, 인명피해는 홍수 발생에 따른 침수면적을 예상하고 인명손실액 및 이재민 피해액이 그와 비례한다고 가정하여 추정하였음 ㅇ낙동강권역 지방하천의 홍수위험지도 4개의 빈도를 활용하여 제공되지 않는 빈도에 대한 침수피해액 내삽으로 편차 발생을 최소화하였고, 각 항목별 피해액의 합인 총 피해액에 연간 생기확률을 곱하여 연 기대피해액을 산정하였음 Ⅴ. 시범지역 침수위험분석 및 홍수위험평가 1. 시범지역(낙동강권역 개요) ㅇ‘2020년 재해연보’에 따르면, 낙동강 유역의 10년간(2011~2020년) 총 홍수피해액은 약 1조 7,922억 1백만 원으로, 동일 기간 전체 홍수피해액 4조 3,757억 84백만 원의 약 41%를 차지하고 있고, 이는 태풍의 영향이 잦을 뿐만 아니라 일반자산 및 인구가 많아 홍수 발생에 따른 침수피해 규모가 크기 때문인 것으로 해석됨 ㅇ중권역별 홍수피해액(2001~2019년)을 살펴보면, 낙동강 본류 상류지역에 비해 하류지역(남강댐, 남강, 낙동밀양, 낙동강하구언)의 피해가 큰 것으로 분석되며, 기타 수계 (낙동강남해, 수영강, 거제도)의 피해액이 높은 것으로 파악됨 ㅇ낙동강권역의 기상청 관할 기상관측소 23곳의 강수량 특성 및 변동성을 분석한 결과, 1976~2020년(총 45년) 부산지역의 연간 강수량과 1일 최대강수량은 대체로 증가하는 경향을 보임 2. 연평균 기대피해액 분석결과 ? 시범지역 대상 연평균 기대피해액 산정 분석 ㅇ연평균 기대피해액의 확률분포함수는 긴 꼬리(long-tail)를 가진 비대칭 분포함수로 분석되었는데, 이는 대부분의 피해수준이 낮게 예상된 가운데, 소수의 침수위험지역에 피해가 집중된 것으로 해석할 수 있음 ㅇ낙동강권역의 홍수위험지역별 예상 피해 규모는 매우 불균등하게 분포되어 있으며, 이는 일률적으로 설정된 하천등급 기반의 하천홍수방어 전략을 침수피해에 따라 차별화해야 할 필요성을 시사함 ㅇ주거자산, 농업자산, 산업자산, 인명피해 중 주거자산 피해가 60%로 가장 높았으며, 다른 항목 대비 산업자산 피해의 비중이 상당히 작은 것은 연구를 지방하천 중심으로 진행했기 때문으로 판단됨 ? 하천별 연평균 기대피해액 분석 ㅇ낙동강권역에 있는 지방하천 중심으로 연평균 기대피해액을 추산한 결과, 해반천(131억 원), 다방천(107억 원), 북천(105억 원), 주천강(92억 원), 상남천(69억 원)에서 가장 큰 것으로 나타남 ㅇ상기 상위 5개 하천은 대규모 피해 예상에도 불구하고 홍수방어목표는 30~100년 빈도의 매우 낮은 수준으로 설정되었으며, 이는 향후 홍수 발생 시 대규모의 침수피해 발생 가능성을 시사함 ? 홍수방어목표와 홍수피해액 간의 관계 ㅇ홍수 침수피해액과 홍수방어목표 간 상관관계는 나타나지 않으며, 오히려 대규모 피해가 예상되는 하천의 홍수방어목표가 50년 빈도의 매우 낮은 수준으로 설정되어 있는 경우도 상당수 발견됨 ㅇ반면 기대피해액이 매우 낮은 수준임에도 불구하고 80년 혹은 100년 빈도로 설정된 하천들 역시 발견되었음 ㅇ대규모 침수피해가 예측된 하천의 경우 홍수방어목표를 상향 조절하고, 반대로 매우 낮은 수준의 침수피해가 예측된 하천의 경우 홍수방어목표를 하향 조절해, 한정된 홍수방어 예산을 효율적으로 사용할 필요가 있으며, 이것이 홍수피해 취약 지점에 대한 홍수방어기준의 개선방향이라고 할 수 있음 ? 민감도분석 ㅇ한국건설기술연구원(2019)에서 제안한 피해함수를 활용해 결과에 대한 민감도분석을 시행하였으며, 피해함수 가정에 따라 피해 추정액이 달라질 수 있지만 하천 간 홍수방어목표의 우선순위는 크게 변하지 않을 것으로 판단됨 Ⅵ. 홍수피해액평가 분석 및 방어제도 정비 1. 홍수 침수피해액 평가 ㅇ연구 분석을 통해 현재 국내 하천별 홍수방어목표는 하천별 기대피해액과 비례하지 않으며, 홍수 발생 시 대규모의 침수피해 발생 가능성이 존재하는 것으로 확인되었음 ㅇ또한 정밀한 영향평가를 통해 하천별 기대침수피해액 추정의 정확도를 높이고, 이와 연계된 정량적 홍수방어목표를 제안할 필요가 있음 ㅇ공공시설, 차량피해, 간접피해 등에 대한 분석은 추후 분석으로 남겨두었으며, 하천별 홍수방어목표를 정량적으로 제시하기보다, 피해액 분석을 통해 대규모 침수피해 예상 하천의 홍수방어목표 상향 및 취약 하천을 우선순위에 둘 것을 제안하였음 2. 홍수방어기준 관련 제도·계획·대책 정비 ? 홍수방어 관련 법령 및 계획 정비 ㅇ??하천기본계획??의 치수종합계획에서 치수목표나 기본방향 설정에 있어 기후변화, 사회·경제적 중요도, 홍수 취약성 고려가 미흡하여 개정이 필요함을 알 수 있음 ㅇ??하천기본계획??의 홍수방어계획에서 계획규모를 초과하는 홍수 발생 가능성을 고려하는 동시에, 사회·경제적 중요성에 대한 정량적 분석을 통해 설계홍수를 추산하여 홍수 피해를 최소화할 것을 제안함 ㅇ??하천기본계획??의 종합치수대책에서 기후변화를 고려하여 하천 중요도를 결정하고, 홍수재해 피해액 추정을 통한 홍수 취약성 분석내용이 추가되어야 할 것으로 판단됨 ㅇ?하천법? 및 ?수자원법?에 기후변화를 고려한 홍수방어기준 및 목표에 대한 구체적인 법률조항 및 계획이 포함되어야 할 것으로 판단됨 ? 홍수방어목표 설정 변화 ㅇ기후변화에 따른 극치수문사상의 강도 및 빈도 증가와 설계빈도를 넘어서는 집중호우로 하천 범람과 도시침수로 인한 홍수피해의 규모가 증가하고 있으며, 이러한 피해를 줄이기 위해 취약성 분석과 함께 피해를 가시적으로 정량화한 분석이 필요함 ㅇ홍수방어 설계빈도를 결정할 때, 정량적 홍수분석을 통해 홍수피해액을 추정하고 홍수 취약성 및 피해잠재력을 정하여, 그에 맞추어 계획 규모를 선택함으로써, 홍수방어목표 결정에 정당성을 부여하고 우선순위를 둘 수 있도록 함 ㅇ홍수 취약성 분석을 통해 사회·경제적 피해 규모가 상당히 큰 지역은 설계빈도를 높여 홍수방어를 강화하는 한편, 주변 지역이 자연녹지나 농업지역일 경우 자연환경이 침해되지 않는 범위에서 설계빈도를 낮추어 방어 대신 적응대책을 설정함 ? 홍수방어기준 개선을 위한 기본전략 ㅇ?수자원법? 및 ?수자원법 시행령? 개선으로 하천 주변의 사회·경제적 변화, 기후변화를 고려한 권역별 홍수위험지도를 10년마다 재작성하여, 지도를 보완하고 정보의 신뢰성을 높일 필요가 있을 것으로 판단됨 ㅇ?수자원법? 제7조의2(홍수피해액지도 작성)를 추가하여 홍수방어목표 및 기준 개선을 위한 홍수피해액지도 작성의 법적 근거를 마련할 필요가 있을 것으로 사료됨 ? 계획의 홍수방어목표 평가체계 구축 필요성 ㅇ??국가물관리기본계획?? 전략에 정량적 홍수위험 분석과 평가를 추가하여 차등화된 방어목표 설정의 근거를 마련하고, 홍수방어평가 제시와 실행력 제고를 위한 이행 평가체계 내용 추가로 평가 결과의 심의·의결을 시행할 수 있는 기반을 마련함 ㅇ?수자원법? 제18조(하천유역수자원계획)의 정량적 홍수위험 분석 추가를 통한 평가 체계 구축과 홍수 침수피해액 분석 기반의 차등화 된 홍수방어기준 수립 관련 내용 추가로 치수계획의 개선방향을 확인할 수 있음 Ⅶ. 결론 및 2차 연도 계획 ㅇ본 연구는 홍수방어 부문의 기후변화 적응대책으로, 정량적 홍수위험분석을 통한 연평균 기대피해액 산정, 하천별·지역별 홍수방어목표의 차등화 기준 마련에 대하여 경제적으로 평가하였음 ㅇ홍수위험지도와 공간인벤토리를 활용하여 홍수 침수피해액을 산정하였으며, 민감도 분석과 더불어 대규모 침수피해가 예상되는 지역의 우선순위 선정과 홍수방어목표 상향의 필요성을 제시하였음 ㅇ?하천법?과 ?수자원법?에서 기후변화를 고려하여 계획을 수립할 것을 제안하였고, 홍수방어 설계빈도에서 홍수 취약성을 고려한 하천등급 설정과 필요 시 설계빈도 상향을 강조하며, 관련 계획인 ??국가물관리기본계획??, ??하천기본계획?? 등에 홍수방어기준 개선 및 평가체계 구축 기반 정립을 모색하였음 ㅇ추후 연구에서는 다양한 기후변화와 사회·경제 발전 시나리오를 활용한 홍수위험평가 및 잠재홍수위험 우선순위 분석을 시행할 예정이며, 해외 주요국의 홍수방어기준 및 관련 부처체계에 대한 구체적 조사로 국내 홍수방어 시스템 개선 방향을 검토하고, 홍수방어를 효과적으로 이행하기 위한 절차를 마련할 예정임


Ⅰ. Introduction 1. Climate change and flood disaster ㅇA report published by the Korea Meteorological Administration (KMA, 2015) stated that global surface temperature is expected to increase throughout the 21st century and that several regions will be highly likely to encounter an increase in the frequency and duration of heat waves and the frequency and intensity of extreme precipitation events. ㅇThis report also indicated that temperature and precipitation will increase by 3 to 14% according to a degree of greenhouse gas emissions and that such increase at the end of the 21st century from 2081 to 2100 will be more considerable than that at the beginning of the 21st century from 2021 to 2040. In this regard, it is predicted that damage caused by disasters, such as flooding, will increase gradually. ㅇThe occurrence of localized heavy rainfalls in South Korea (Korea) has shown a trend of increase since the early 1900s. Based on this trend, it is analyzed that the scale of flood damage may increase due to extremely heavy rainfall in a short period and localized torrential rainfall. ㅇHeavy rain that poured in the last ten years (from 2011 to 2020) resulted in loss of lives of 139 people, and the death toll increases to 182 persons when the number of deaths caused by flooding is also counted. Heavy rain that poured in the corresponding period caused damage equivalent to 2.1557 trillion won (KRW), and the total cost of damage increases to 4.1126 trillion won when damage caused by flooding is also counted. As such, Korea has constantly suffered from damage caused by flooding. 2. Necessity and purpose of research ? Necessity of research ㅇThe flood defense level applied for rivers in Korea is classified according to river grades. However, the ultimate goal of flood defense is to prevent flood damage to local communities. In this regard, the floor defense level should be determined based on quantitative impact assessment to reduce flood damage in consideration of the surrounding conditions. ㅇThe Korean government announced the master plan for national water management based on the period ranging from 2021 to 2030, a top-level national plan that encompasses the entire water management plans in each relevant field according to Article 27 of the Framework Act on Water Management. As for strategic tasks in each field, this plan presents strategies for developing systems for guaranteeing safety from water-related disasters to emphasize the necessity of establishing a flood response system and strengthening a flood management system according to water-related disasters and particularly climate change. ㅇThe River Act and the Act on the Investigation, Planning, and Management of Water Resources were transferred to the Ministry of Environment after unification of water management. The Korean government has established flood defense and control plans based on the basic river plan under the River Act and the river basin water resource management plans under the Act on the Investigation, Planning, and Management of Water Resources. It also enacted the Framework Act on Water Management, for which the Ministry of Environment is responsible, and designed the master plan for national water management and the comprehensive basin water management plan according to the corresponding Framework Act. As indicated in the aforementioned actions, it has constantly prepared measures for reducing water-related disasters, such as flooding, and responding to vulnerability to water management. ? Purpose of research ㅇThis study aimed to establish the base for policies on implementing mainstreaming of adaptation to climate change and ultimately provide the foundation for adaptation to climate change, such as enhancement of tools for assessing the impacts of climate change and vulnerability to climate change and reinforcement of systems for evaluating adaptation to climate change and reflecting climate change risks. To this end, it quantitatively analyzed flood risks by examining cost of flood damage according to frequency of floods and determined a standard for flood risk level by considering climate change as well as social and economic changes. ㅇIt also intended to review the necessity of elevating and differentiating flood defense levels and to derive relevant political implications. To this end, it presented a method of calculating expected flood damage caused by flood events according to regions and rivers. Then, it conducted a case analysis to compare the expected annual damage according to rivers with the current flood defense level. Based on the analytic result, it identified rivers that were expected to cause large-scale flood damage. 3. Contents and range of research ? Contents of research ㅇThis study enhanced flood defense criteria by considering climate change, revised relevant laws and plans, and analyzed economic feasibility of flood damage. Accordingly, it presented a direction for establishing flood control plans. ㅇIt calculated flood damage cost depending on the range and depth of floods by using information on flood risks according to frequency of floods, which is indicated on the flood risk map provided by the Ministry of Environment. It also evaluated vulnerability to flood disaster to examine a degree of flood damage. ㅇIt investigated current policies and plans on flood defense executed by relevant ministries as of 2022 and analyzed implications of revised laws and plans to present a direction for establishing a selective and differential flood defense level determination system. ? Range of research ㅇIn the first year of research, this study proposed a method of quantifying expected economic risks of life and property damage according to frequency of floods based on local rivers in the Nakdong River zone. It also estimated the cost of flood damage according to rivers and reviewed vulnerability to flood disaster. In the second year of research, it quantitatively analyzed flood risks by considering scenarios on climate change and social and economic development. Then, it presented flood defense criteria and a differentiated flood defense level determination system, both of which reflect climate change and the analytic results, to propose flexible flood response methods. ㅇIn the first and second years of research, this study derived the results of a quantitative analysis of flood disaster risks, which reflected climate conditions as well as social and economic conditions, and an analysis depending on various scenarios. Subsequently, it proposed policy support tools that can analyze the cost effect of policies on adaptation to climate change by applying the analytic results. Yet, it did not review alternative methods for estimating required cost for flood defense and implementing flood defense. 4. Definition of relevant concepts to research ㅇA quantitative flood risk analysis is a process of quantitatively examining flood risks by evaluating loss caused by flood and value of risk assets. In this analysis, a risk caused by an unwanted flood disaster is defined in a monetary (quantitative) form. ㅇThis study referred to the following main terms on flood defense: -Expected annual damage: the accumulated cost of flood damage that is determined by calculating flood damage cost according to the frequency of floods and multiplying the calculated value with a probability of annual occurrence - Flood damage map: A map that visually represents the expected annual damage - Flood defense criterion: a standard established to prevent flood damage in a frequently flooded region or an area with a high disaster risk -Vulnerability analysis: a process of examining potential risks of floods by reflecting current and expected future conditions of population, industries, residential houses and structures, public facilities, and farmland according to rivers and regions Ⅱ. Laws and Plans on Flood Defense in Korea 1. The Framework Act on Water Management and the master plan for national water management ㅇThe Framework Act on Water Management does not include specific regulations on flood defense but contains those on flood management according to basins as basic principles of water management. This act specifies prevention of disasters caused by floods and establishment of plans for prevention of flood disasters. ㅇThe master plan for national water management presents a shift of a direction for management from uniform management, which considers only facilities, previous climate conditions, and river grades, to selective and focused management, which considers uncertainty of future according to climate change, areas expected to be damaged, and expected scale of damage. This plan also states objectives for flood defense reflecting climate change and social and economic significance as tasks to be implemented. 2. The River Act, the Act on the Investigation, Planning, and Management of Water Resources, and relevant plans ㅇIn terms of flood defense, the River Act states matters concerning designation, management, use, and conservation of rivers to prevent flood damage. Article 25 of the Basic River Plans, a relevant plan to the River Act, determines flood defense criteria and goals. ㅇThe Act on the Investigation, Planning, and Management of Water Resources stipulates matters concerning survey of water resources, formulation and implementation of water resource plans, and efficient management of water resources to mitigate and prevent water-related disasters. Relevant plans include Article 17 of the Comprehensive Long-term Water Resources Plan, which has not been implemented since 2021, Article 18 of the Plan on Management of Water Resources of River Basins, Article 19 of the Regional Water Resources Management Plan, and Article 20 of the Plan on Flood Prevention in Specific Basins. 3. The Framework Act on the Management of Disasters and Safety and relevant plans ㅇThe Framework Act on the Management of Disasters and Safety intends to establish disaster and safety management systems of the State and local governments and to prescribe matters necessary for the disaster prevention, preparedness, response, and recovery and disaster and safety management in order to preserve national land against various disasters and to protect citizens’ lives, bodies, and property. ㅇThe Framework Act on the Management of Disasters and Safety is a fundamental law for disaster management, whereas it does not include specific regulations on flood defense. Relevant plans include the Master Plan for National Safety Management, City/Do safety management plans, Si/Gun/Gu safety management plans, function continuity plans, and action plans for disaster response, which provide various regulations on disaster prevention, preparedness, response, and recovery. 4. The Countermeasures against Natural Disasters Act and relevant plans ㅇThe Countermeasures against Natural Disasters Act states comprehensive regulations on damage caused by storm and flood and presents flood prevention standards by district applied to perform flood defense against floods caused by increased river flow. ㅇThis act contains regulations on targets for performance of disaster prevention, which present a policy goal for prevention of disasters caused by floods and rainfalls based on the amount of rainfalls. Relevant plans include a comprehensive plan to upgrade living areas damaged by storms and floods and a comprehensive plan to mitigate natural disasters. 5. The National Land Planning and Utilization Act and relevant plans ㅇAs the River Act and the Act on the Investigation, Planning, and Management of Water Resources were transferred to the Ministry of Environment, the Ministry of Land, Infrastructure and Transport (MOLIT) does not present any legislation directly related to flood defense criteria and goals. ㅇHowever, the MOLIT newly established a regulation on an analysis on disaster vulnerability in the National Land Planning and Utilization Act in June 2015 to evaluate disaster vulnerability of inland near rivers and to reflect the evaluation results in urban planning. A relevant plan includes an urban or Gun management plan. 6. Implications ㅇThe Korean government has implemented comprehensive changes of its governmental organizations responsible for water management and national top-level laws and plans, as shown its actions such as unification of water management and establishment of the Framework Act on Water Management and the master plan for national water management. It has also discussed the necessity of enhancing lower laws of the the master plan for national water management as well as relevant laws and plans to this act. ㅇThe Korean government should review relevant laws and plans to adjust a basic direction for establishing goals of and criteria for flood defense, which reflect climate change. It should also develop specific quantitative analysis tools and methodologies for determining these criteria in detail. Furthermore, it should present a direction for establishing a flood defense plan evaluation system to efficiently formulate a flood defense plan. Ⅲ. Cases of Research on Estimation of Cost of Flood Damage in Korea 1. A simple method ㅇA simple method calculates cost of damage to agriculture by multiplying coefficients of other damaged items by cost of damage to crops. This method was first used after it was mentioned in a standard on river facilities proposed by the Ministry of Works (now the MOLIT) in 1993. ㅇAgricultural assets accounted for a great proportion of the entire flood damage that occurred in Korea during the period when the simple method was developed. This method showed limited performance for detailed estimation in terms of data and techniques that can be used. 2. An enhanced method ㅇAn enhanced method is an advanced version of the simple method based on a regression equation that uses the size of flooded area as a variable to calculate flood damage. This method was proposed in a previous study on the economic analysis in flood control projects, which particularly focused on a river maintenance project executed in 2001. ㅇThis existing study emphasized the amount of rainfalls and the size of flooded area as elements that exert the greatest influence on the amount of damage caused by river flooding. It analyzed a relationship between the identified elements and the amount of damage caused by river flooding by classifying target regions into a major city, a small and medium-sized city, a garden city, a rural region, and a mountainous region according to the size of a city and types of areas. 3. A multi-dimensional method ㅇA multi-dimensional method uses a geographic information system (GIS) to analyze various types of statistical and spatial data related to the size of assets and spatial distribution in a target region. This estimation technique has been used for practical tasks since it was developed in 2004. ㅇThe multi-dimensional method calculates a ratio of the flooded area to the entire area based on the size of land for residential use and uses this ratio to distribute the asset value of each flooded area. The calculated ratio of the flooded area to the entire area is multiplied by the results of analyzing the assets of administrative districts, which were determined in advance. Through these processes, the multi-dimensional method determines the asset value of a district practically damaged by flooding. 4. An object-based method ㅇAn object-based method applying asset data (inventories) of high resolution and a damage function, which reflects conditions in Korea, has emerged as a technique for solving the problems of the multi-dimensional method. ㅇThe object-based method can perform a high-resolution spatial unit analysis based on spatial data. In this regard, this method is more advantageous than the multi-dimensional method that ignores spatial characteristic of each building and asset due to the use of the mean of values obtained from each region. The object-based method can significantly reduce a difference between the estimated amount of damage and the practical amount of damage. 5. Implications ㅇThe currently used multi-dimensional method estimates the amount of flood damage by identifying a flooded area and using data of average assets of an administrative district that includes the identified flooded area. However, this method has a problem that it uses the mean of values obtained from each region and does not consider spatial characteristics of each asset. For this reason, it results in a considerable difference between the estimated amount of damage and the practical amount of damage. ㅇAn object-based method reduces a difference between the estimated amount of data and the practical amount of damage by performing a high-resolution spatial unit analysis based on spatial data. ㅇThis study conducted an analysis based on the unit of a 100 m grid by using spatial data obtained by a GIS to increase reliability and accuracy of flood damage calculation. Ⅳ. Establishment of Data of Flood Risk Maps and Spatial Inventories 1. Case analysis of flood risk maps ? Overview of the flood risk map ㅇA non-structural flood defense measure refers to an activity of removing or reducing flood damage without accompanying construction of a structure for flood defense or control. In other words, this flood management plan is executed to comprehensively lower the range and damage of flooding. ㅇA flood risk map is a non-structural flood defense measure that can overcome the limitations of Korea’s previous flood prevention policies, which focused on structural flood defense measures. It provides essential information that can be used to analyze occurrence of floods and figure out the influence range of floods. It can be applied in the entire processes of flood management, including formation of flood reduction measures, prior preparation for flood damage, prevention of flood damage, and relevant restoration. ㅇThe flood risk map is a special-purpose map for basic data management, which supports development of both structural and non-structural measures for establishing flood defense plans. ? Background of implementation and formation of the flood risk map in Korea ㅇThe flood risk map was initially called flood map when first introduced in Korea. The Korean government first enacted regulations on this map and renamed it to flood risk map according to the revised River Act in 2007. The flood risk map mainly predicts the range and depth of inundation caused by river flooding. It consists of both a map of flood risks caused by river flooding and a map of inland flooding risks caused by an excess of the designed amount of rainfalls. ㅇAs for current legal standards on the flood risk map, Article 7 of the Act on the Investigation, Planning, and Management of Water Resources defines the flood risk map as a “map for predicting a risk of flood damage.” Article 21 of the Countermeasures against Natural Disasters Act states that a disaster map consists of a flood map, a flooding prediction map, and a disaster information map. ? Standards on formation of the flood risk map in Korea ㅇThe spatial range of the map of flood risks caused by river flooding comprises both the area of the target river including its branches and that of flood plains affected by simulated flooding. The inland flooding risk map shows drainage areas that encounter inland flooding damage caused by simulated situations, such as occurrence of rainfalls, increased external water level, and a failure of a pump station, when the amount of rainfalls exceeds the designed amount of rainfalls. ㅇTo simulate virtual inland flooding situations, conditions for occurrence of flooding should be assumed. A flooding scenario is classified according to conditions of a basin, the scale of flooding (or the scale of rainfall for a case related to inland), and flooding (inland flooding for a case related to inland). 2. Overview of a spatial inventory ? Methods for establishment of a spatial inventory and a range of the spatial inventory ㅇThis study calculated expected annual damage by adopting methods developed by the Ministry of Construction & Transportation (now the MOLIT) (2001) and the Korea Development Institute. Moreover, it increased reliability and accuracy of expected annual damage by actively using spatial data obtained by a GIS. ㅇThis study is significantly distinguished from previous studies in that it calculated expected annual damage according to the unit of space based on the size of 100m (100m × 100m) in high resolution instead of the unit of an administrative district such as Si, Gun, Gu, Eup, Myeon, and Dong. It evaluated expected annual damage in approx. 468 million areas to analyze cost of flood damage that were incurred in the Nakdong River zone. ㅇThis study examined data of floods that occurred in 798 local rivers and streams that belong to the Nakdong River zone according to four return periods (50 years, 80 years, 100 years, and 200 years). It established the year 2019 as a reference year for a more convenient analysis of current statistics. ? Methods of calculating cost of flood damage (expected annual damage) according to damaged items ㅇIn the first year of research, this study analyzed expected annual damage based on four types of damaged items (residential assets, agricultural assets, industrial assets, and life damage) by considering the absence of systematic data acquisition and calculation methods. ㅇThis study developed a database (DB) of general assets, such as residential assets, agricultural assets, and industrial assets, according to each region. Then, it calculated expected annual damage based on the established DB. To calculate expected annual damage based on life damage, this study estimated the size of flooded area and assumed that cost of loss of human lives and cost of damage applied to flood victims were proportional to the estimated size of flooded area. ㅇThis study examined flood damage caused by local rivers and streams in the Nakdong River zone according to four return periods applied in the flood risk map to interpolate flood damage, which were calculated based on return periods that were not provided, and to ultimately minimize bias. Subsequently, it determined expected annual damage by multiplying the entire flood damage cost, the sum of flood damage cost according to items, by a probability of annual occurrence. Ⅴ. Analysis and Evaluation of Flood Risks in a Model Area 1. Designation of the Nakdong River zone as a model area ㅇThe 2020 annual disaster report showed that the entire flood damage cost in the Nakdong River zone for ten years from 2011 to 2020 was approx. 1,792,201,000,000 won. This cost accounted for approx. 41% of the entire flood damage cost (approx. 4,375,784,000,000 won) in Korea for the same period. This study analyzed that this result was derived due to not only the influence of typhoons that frequently took place in the Nakdong River zone but also a large scale of flood damage affected by the great amount of general assets and high population in the corresponding zone. ㅇThe result of analyzing flood damage cost according to middle zones from 2001 to 2019 showed that flood damage in the downstream regions (the Namgang dam, Mirayng-si, and the Nakdong River estuary bank) of the Nakdong river was greater than that in the upstream regions of the Nakdong river. Flood damage was also great in other regions (the South Sea, the Suyeong river, and Geoje-do) related to the Nakdong river. ㅇThis study investigated the characteristics and volatility of precipitation observed by 23 meteorological observatory sites under the jurisdiction of the KMA, which are included in the Nakdong River zone. The investigation result showed a trend of an increase in the annual amount of precipitation and the amount of maximum daily precipitation per year for 45 years from 1976 to 2020 in Busan, Korea. 2. Analytic results of expected annual damage ? Analysis of expected annual damage in the model area ㅇThis study found that the probability distribution function of expected annual damage calculated in this study was an asymmetric distribution function with a long tail. This result was derived due to the following reasons. First, most flooding-prone areas were expected to encounter a low level of flood damage. Second, flood damage was concentrated in a few flooding-prone areas. ㅇThe scale of expected flood damage in flooding-prone areas in the Nakdong River zone showed significantly uneven distribution. This result implies that the Korean government should replace the existing river flood defense strategies according to river grades, which were established without reflecting flexible conditions, with more differentiated river flood defense strategies according to flood damage. ㅇResidential assets received the greatest flood damage among agricultural assets, industrial assets, and human lives. The amount of flood damage to residential assets accounted for 60% of the entire amount of flood damage to the four damaged items. In addition, the amount of flood damage to industrial assets accounted for the lowest proportion of the entire amount of flood damage to the four damaged items. This result was obtained because this study focused on local streams. ? Analysis of expected annual damage according to rivers and streams ㅇThis study calculated expected annual damage based on local rivers and streams that belonged to the Nakdong River zone. The calculation result showed that the Haeban stream will accompany the greatest expected annual damage (13.1 billion won), followed by the Dabang stream (10.7 billion won), the Buk stream (10.5 billion won), the Jucheon river (9.2 billion won), and the Sangnam stream (6.9 billion won). ㅇAlthough the aforementioned five rivers and streams were expected to bring large-scale flood damage, the flood defense level for these rivers and streams was established at low level based on return periods from 30 years to 100 years. Based on these conditions, it was analyzed that large-scale flood damage may occur in areas related to the aforementioned rivers and streams in the future. ? A relationship between the flood defense level and flood damage cost ㅇThis study found that there was not any relationship between the flood defense level and flood damage cost. In several cases, the flood defense level of rivers and streams, which were expected to bring large-scale flood damage, was established at significantly low level based on the return period of 50 years. ㅇOn the other hand, other cases showed that the flood defense level of multiple rivers and streams, which were expected to cause low-scale expected flood damage, was established at high level based on the return period of 80 years or 100 years. ㅇThe Korean government should increase the flood defense level of rivers and streams, which are expected to cause large-scale flood damage, and decrease the flood defense level of rivers and streams, which are expected to generate low-scale flood damage, to efficiently use a limited budget for flood defense. This approach is regarded as a direction for improving flood defense criteria in consideration of vulnerable points to flood damage. ? Sensitivity analysis ㅇThis study carried out a sensitivity analysis of the estimated results by using a damage function developed by the Korea Institute of Civil Engineering and Building Technology (2019). Estimated flood damage cost can vary according to an assumption applied for the damage function. However, it is analyzed that the priority of the flood defense level of rivers and streams will not be significantly affected by such assumption. Ⅵ. Evaluation of Estimated Flood Damage and Enhancement of Flood Defense Systems 1. Evaluation of flood damage ㅇThis study found that the current flood defense level of rivers and streams in Korea was not proportional to expected damage to be caused by these rivers and streams. Moreover, it verified that these rivers and streams is likely to cause large-scale flood damage in case of flooding. ㅇFurther research should be conducted to increase the accuracy of calculation of expected flood damage according to rivers and streams through more specific impact assessment. In addition, follow-up research should quantitatively present the flood defense level based on more accurate results on expected flood damage derived. ㅇAdditional research should also be conducted to analyze direct and indirect flood damage to public facilities, vehicles, and other items. This study did not present quantitative flood defense levels according to rivers. Rather, this study suggested a need for the rising of the flood defense level of rivers and streams, which are expected to cause large-scale flood damage. It also presented the priority of flooding-prone rivers and streams for elevation of the flood defense level. 2. Enhancement of policies, plans, and measures on flood defense criteria ? Improvement of laws and plans on flood defense ㅇA comprehensive flood prevention plan, a part of the basic river plan, includes insufficient contents related to setting of flood prevention goals and consideration of climate change, social and economic significance, and vulnerability to flooding. This problem emphasizes a need for revision of the comprehensive flood prevention plan. ㅇThe Korean government should develop a flood defense plan under the basic river plan by reflecting a possibility of occurrence of floods whose scale exceed the designed scale. It should also calculate design flood by applying social and economic significance to a quantitative flood analysis and adopt the optimal flood defense plan to minimize flood damage. ㅇThis study analyzes that a comprehensive flood prevention plan under the basic river plan should include contents on determining the priority of rivers and streams by considering climate change. This plan should also contain contents on an analysis of vulnerability to flooding based on estimated flood damage. ㅇThis study analyzes that the River Act and the Act on the Investigation, Planning, and Management of Water Resources should provide specific regulations and plans on flood defense criteria that reflect climate change and relevant goals. ? Change in establishment of the flood defense level ㅇClimate change has increased the intensity and frequency of extreme hydrologic events and generated localized heavy rainfalls that exceed the return period of flood defense structures. The phenomena have increased the scale of flood damage caused by river flooding and urban inundation. To reduce such flood damage, a vulnerability analysis and a quantitative and economic analysis of flood damage should be carried out. ㅇIn the process of establishing the return period of flood defense structures, a quantitative flood analysis should be conducted to calculate expected flood damage and to determine vulnerability to flooding and potential damage. Based on the determined values, the scale of a flood defense plan should be selected. These processes ensure validity for determining and differentiating flood defense levels. ㅇThe Korean government should conduct an analysis of vulnerability to flooding and increase the return period of flood defense structures in a region, which is expected to face socially and financially significant flood damage, to reinforce flood defense. If the target region is surrounded by a natural green area or an agricultural area, the Korean government should adopt a measure of adaptation to climate change instead of a flood defense measure by lowering the return period of flood defense structures within a range that does not harm natural environment. ? General strategy for improving flood defense criteria ㅇThis study evaluates that the Korean government should revise the Act on the Investigation, Planning, and Management of Water Resources and the Enforcement Decree of the Act on the Investigation, Planning, and Management of Water Resources to renew and enhance flood risk maps according to zones, which consider social and economic changes in adjacent areas to the corresponding river or stream, and climate change, at the interval of ten years, and to increase reliability of information provided by these maps. ㅇThis study also suggests that the Korean government should add Article 7(2) (Formation of the Flood Damage Map) of the Act on the Investigation, Planning, and Management of Water Resources to provide legal grounds for establishment of flood damage maps and to ultimately enhance a flood defense level determination system and relevant criteria. ? Necessity of development of a flood defense level evaluation system for plans ㅇThe master plan for national water management Quantitative flood should include risk analysis and evaluation as a flood defense strategy to provide grounds for establishment of differentiated flood defense goals. This plan should also contain contents on a system for assessing the performance of flood defense to introduce flood defense evaluation, to increase power of execution for flood defense, and to provide grounds for reviewing and passing flood defense evaluation results. ㅇArticle 18 (River Basin Water Resource Management Plans) of the Act on the Investigation, Planning, and Management of Water Resources should include contents on establishment of a flood defense evaluation system based on a quantitative flood risk analysis and those on implementation of differentiated flood defense criteria based on a flood damage analysis to reflect a direction for enhancement of flood prevention plans. Ⅶ. Conclusions and Plans for the Following Year ㅇThis study calculated expected annual damage based on a quantitative flood risk analysis to propose a measure for adapting to climate change in the flood defense field. It also evaluated the economic feasibility of preparation of a differential flood defense level determination system according to rivers, streams, and regions. ㅇThis study calculated flood damage cost by using flood risk maps and spatial inventories. It also conducted a sensitivity analysis and presented the priority of regions, which were expected to receive large-scale flood damage, for elevation of the flood defense level. Accordingly, it described a need for elevation of the flood defense level in these regions. ㅇThis study stated that the Korean government should consider climate change in the process of establishing flood defense plans under the River Act and the Act on the Investigation, Planning, and Management of Water Resources. It also emphasized the necessity of determining river grades in consideration of vulnerability to flooding and that of increasing the return period of flood defense structures when needed. Furthermore, it suggested that relevant plans to flood defense, such as the master plan for national water management and the basic river plan, should include contents on establishment of systems for enhancing and evaluating flood defense criteria. ㅇFurther research will be conducted to perform flood risk evaluation and an analysis of priority of potential flood risks by applying various types of climate change scenarios and social and economic development scenarios. Moreover, following-up research will intensively investigate flood defense criteria and systems of relevant ministries in other major countries to review a direction for improving Korea’s flood defense systems and to effectively implement flood defense in Korea.

Table Of Contents

요 약

제1장 서론
1. 기후변화와 홍수재해
2. 연구의 필요성 및 목적
3. 연구내용 및 범위
4. 연구 관련 개념 정의

제2장 국내 홍수방어법령 및 계획
1. 물관리기본법 및 국가물관리기본계획
2. 하천법·수자원법 및 관련 계획
3. 재난 및 안전관리 기본법 및 관련 계획
4. 자연재해대책법 및 관련 계획
5. 국토계획법 및 관련 계획
6. 시사점

제3장 국내 홍수피해비용 산정 연구사례
1. 간편법
2. 개선법
3. 다차원법
4. 객체기반법
5. 시사점

제4장 홍수위험지도 및 공간인벤토리 자료 구축
1. 홍수위험지도 개요
2. 공간인벤토리 개요

제5장 시범지역 침수위험분석 및 홍수위험평가
1. 시범지역(낙동강권역 개요)
2. 연평균 기대피해액 분석결과

제6장 홍수피해액평가 분석 및 방어제도 정비
1. 홍수 침수피해액 평가
2. 홍수방어기준 관련 제도·계획·대책 정비

제7장 결론 및 2차 연도 계획

참고문헌

Executive Summary

Appears in Collections:
Reports(보고서) > Climate Policy(기후환경정책연구)
Files in This Item:
Export
RIS (EndNote)
XLS (Excel)
XML

qrcode

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

Browse