标准编号:	GB 50400-2016
中文名称:	建筑与小区雨水控制及利用工程技术规范
英文名称:	Technical code for rainwater management and utilization of building and sub- district
行业分类:	GB    国家标准
发布机构:	中华人民共和国住房和城乡建设部
发布日期:	2016-10-25
实施日期:	2017-7-1
标准状态:	现行
替代旧标准:	GB 50400-2006 建筑与小区雨水利用工程技术规范
翻译语言:	英文
文件格式:	PDF
中文字符数:	50000 字
翻译价格(元):	6000.00 元
交付时间:	付款后 1 个工作日

Technical code for rainwater management and utilization of building and sub-district



1 General provisions



1.0.1 In order to build a low-impact development system for urban source rainwater, develop or repair the water environment and ecological environment, realize total runoff control, peak runoff control, and runoff pollution control of source rainwater, and make low-impact development rainwater system projects in buildings, sub-districts and factories technologically advanced, economically reasonable, safe and reliable, this code is developed.



1.0.2 This code is applicable to the planning, design, construction, acceptance, and operation management of rainwater management and utilization engineering in sponge-type civil buildings and sub-districts, industrial buildings, and factories. This code is inapplicable to rainwater utilization engineering where rainwater is used as a source of drinking water.



1.0.3 Rainwater management and utilization engineering shall reasonably adopt various technologies for developing rainwater systems with low impact according to the specific conditions of the engineering, local water resources conditions, and economic development level.



1.0.4 Rainwater management and utilization engineering may adopt technical measures such as infiltration, stagnation, detention, purification, use, and drainage.



1.0.5 Planning and design stage documents shall include the contents on rainwater management and utilization. Rainwater management and utilization equipment shall be planned, designed, constructed, and put into use simultaneously together the main engineering of the project.



1.0.6 Rainwater management and utilization engineering shall take measures to ensure personal safety, use, and maintenance safety.



1.0.7 Rainwater management and utilization engineering shall be designed in conjunction with outdoor general plan, landscape, architecture, water supply and drainage, and other specialties.



1.0.8 The planning, design, construction, acceptance, operation management of rainwater management and utilization engineering of buildings and sub-districts shall also meet the requirements of the relevant current national standards in addition to complying with this code.



2 Terms and symbols



2.1 Terms



2.1.1

rainwater management and utilization

general term for total runoff, peak runoff, and runoff pollution control equipment, including rainwater infiltration (permeability), harvesting and reuse, detention and controlled drainage, etc.



2.1.2

volume capture ratio of annual rainfall

percentage of the cumulative annual managed rainfall in the site in the total annual rainfall according to the statistical analysis and calculation of multi-year daily rainfall



2.1.3 漏掉了



2.1.4

underlying surface

a general term for surface receiving water including roof, ground, water surface, etc.



2.1.5

permeability coefficient of soil

steady infiltration velocity of water per unit hydraulic slope



2.1.6

pluviometric runoff coefficient

ratio of the total amount of runoff produced by rainfall to the total amount of rainfall over a set time



2.1.7

impervious surface

impermeable ground formed by hardening the natural ground through artificial actions



2.1.8

initial runoff

pluviometric runoff with certain thickness at the initial stage of rainfall



2.1.9

initial rainwater removal equipment

facility that utilizes rainfall amount and rainwater runoff thickness to control initial runoff discharge including automatic control removal well, infiltration-removal well, removal pool, etc.



2.1.10

infiltration-removal well

device with a certain storage volume and sewage interception function to infiltrate the initial runoff into the underground



2.1.11

infiltration equipment

facility that stores rainwater runoff flow and perform infiltration, including infiltration ditch, infiltration pool, infiltration well, pervious pavement, etc.



2.1.12

infiltration pool

buried pool where rainwater infiltrates through the side walls and bottom of the pool



2.1.13

infiltration well

facility where rainwater infiltrates through sidewalls and bottoms of the well



2.1.14

infiltration-drainage pipe system

system in which infiltration manholes and infiltration pipes are used to infiltrate rainwater into the underground in an organized way, and rainwater exceeding the infiltration design standard is discharged from pipe trench



2.1.15

pervious pavement

ground pavement structure composed of permeable top layer, base layer, sub-base layer, etc. which can store and infiltrate the rainfall it receives



2.1.16

grass swale

facility with vegetation planted in swale on the surface, which can intercept rainwater and infiltrate it, or transfer rainwater and use vegetation to purify it



2.1.17

infiltration trench

rainwater drain or ditch with infiltration function



2.1.18

infiltration manhole

pipe inspection and maintenance device with penetration function and certain grit settling volume



2.1.19

collect-infiltration manhole

pipe inspection and maintenance device with a top cover that collects ground rainwater, which has penetration function and a certain grit settling volume



2.1.20

rainwater storage equipment

facility for storing untreated rainwater



2.1.21

wet pond

landscape water body with rainwater detention, control and purification functions, which uses rainwater as the main water replenishment source



2.1.22

detention and controlled drainage equipment

facility that stores rainwater for a certain period of time, reduces the peak runoff of rainwater discharged downstream, and extends the discharge time



2.1.23

bioretention system, bioretention cell

facility for detention storage, infiltration and purification of runoff rainwater through plants, soil and microbial systems



2.2 Symbols



2.2.1 Flow, water amount



Q——inflow of regulating and detention pool;



Q ——design flow of outlet pipe;



Qy——treatment capability of equipment;



Vh——water storage capacity of rainwater storage equipment of harvesting and reuse system;



VL——amount of rainwater intercepted by rainwater management and utilization equipment;



VL1——amount of rainwater intercepted by infiltration equipment;



VL2——amount of rainwater intercepted by harvesting and reuse equipment;



VL3——amount of rainwater intercepted by detention and controlled drainage equipment;



Vs——amount of rainwater detained by detention infiltration system;



Vt——water storage capacity of rainwater storage equipment of detention and controlled drainage system;



W——total amount of rainwater runoff that needs to be managed and utilized;



W1——design runoff of rainwater on the catchment surface of infiltration equipment;



W2——design runoff of rainwater on the catchment surface of harvesting and reuse system;



Wc——water inflow of infiltration equipment;



Ws——amount of infiltration;



Wi——initial runoff removal flow;



Wp——total amount of water excluded from development site;



Wx1——amount of rainwater infiltrated when the amount of rainwater accumulated in the infiltration equipment reaches the maximum value;



Wy——maximum daily water consumption of the reuse system;



q——design rainstorm intensity;



qc——intensity of rainstorm corresponding to the runoff duration of the infiltration equipment;



qi——maximum daily water quota for certain type of water users.



2.2.2 Head loss, geometric characteristics



As——effective permeation area;



F——area of impervious catchment surface;



F0——direct water receiving area of infiltration equipment;



Fy——catchment area received by infiltration equipment;



Fz——total area of development site;



hy——daily rainfall in design;



hp——daily rainfall in drainage design;



δ——initial runoff removal thickness;



2.2.3 Calculation coefficients and others



A, b, c, n——parameters of local rainfall;



J——hydraulic gradient;



K——permeability coefficient of soil;



fk——rainwater management and utilization rate of development site;



ni——number of certain type of water users;



α——comprehensive safety coefficient;



Ψ0——runoff coefficient corresponding to the managed runoff peak, which shall meet the local planning control requirements;



Ψc——pluviometric runoff coefficient;



Ψz——comprehensive pluviometric runoff coefficient of development site.



2.2.4 Time



P——design recurrence interval;



T——daily operating time of rainwater treatment equipment;



t——duration of rainfall;



t1——catchment time of catchment surface;



t2——time of flow for rainwater in pipe trench;



tc——runoff duration of the infiltration equipment;



tm——water storage duration of regulating and detention pool;



ts——infiltration duration;



ty——water use duration.



3 Water quantity and water quality



3.1 Rainfall and rainwater quality



3.1.1 Rainfall shall be determined according to the local rainfall data of more than 20 years. When the data is lacking, the values in Annex A to this code may be used.



3.1.2 The total annual rainwater runoff in the development land shall be managed, and the management rate and corresponding design rainfall shall meet the requirements of local sponge city planning management indicators.



3.1.3 The peak value of rainwater runoff shall be managed in the development land, and the total amount of rainwater runoff that needs to be managed and utilized shall be calculated using the following equation. When hydrological and rainfall data are available, it can also be determined according to the analysis of multi-year rainfall data.



W=10(Ψc-Ψ0)hyF (3.1.3)



where,



W——the total amount of rainwater runoff that needs to be managed and utilized, m3;



Ψc——pluviometric runoff coefficient;



Ψ0——the runoff coefficient corresponding to the managed runoff peak, which shall meet the local planning management requirements;



hy——the daily rainfall in design, mm;



F——the catchment area of impervious surface, hm2, which shall be calculated according to the horizontal projected area of the impervious catchment surface.



3.1.4 The pluviometric runoff coefficient should be adopted according to Table 3.1.4, and the comprehensive runoff coefficient of the catchment area shall be calculated according to the weighted average of the type of underlying surface.



 

Table 3.1.4 Rainfall runoff coefficient

Type of underlying surface Pluviometric runoff coefficient, ψc

Hard roof, unstoned flat roof, asphalt roof 0.80~0.90

Flat roof paved with stones 0.60~0.70

Green roof 0.30~0.40

Concrete and asphalt pavement 0.80~0.90

Pavement with rubbles, etc. 0.50~0.60

Dry brickwork and gravel pavement 0.40

Unpaved soil pavement 0.30

Green land 0.15

Water surface 1.00

Green land covered with soil for underground buildings (thickness of covering soil≥500 mm) 0.15

Green land covered with soil for underground buildings (thickness of covering soil< 500 mm) 0.30~0.40

Pervious pavement ground 0.29~0.36



3.1.5 The daily rainfall in design shall be determined according to the annual maximum 24-hour rainfall, which can be determined according to the provisions of 3.1.1 of this code or local rainfall data, and shall not be less than the design rainfall corresponding to the local total annual runoff management rate.



3.1.6 The area of impervious catchment surface shall be calculated according to the sum of the areas of impervious surface, non-green roof, and water surface, and the area of pervious pavement ground shall be deducted.



3.1.7 The water quality of roof rainwater after initial runoff removal should be determined based on local measured data. When there is no measured data, the following empirical values may be used: CODCr 70 mg/L to 100 mg/L; SS 20 mg/L-40 mg/L; Chroma 10 degrees~40 degrees.



3.1.8 The total amount of pollutants discharged into municipal rainwater pipes should be managed. The quality of rainwater discharged into urban surface water bodies shall meet the water quality requirements of the water body.



3.2 Rainwater resource utilization and water quality



3.2.1 The maximum daily water consumption for greening, road and square watering, garage floor washing, vehicle washing, circulating cooling water replenishment, etc. shall be implemented in accordance with the provisions of the current national standard GB 50015 Standard for design of building water supply and drainage, and the average daily water consumption shall be implemented in accordance with the current national standard GB 50555 Standard for water saving design in civil building.



3.2.2 The maximum daily flushing water consumption for various types of buildings shall be implemented in accordance with the current national standard GB 50336 Standard for design of building reclaimed water system.



3.2.3 The water replenishment amount of landscape water body shall be comprehensively determined according to local water surface evaporation and water infiltration, water treatment self-consumption and other factors.



3.2.4 The water quality of the reused rainwater centralized supply system shall be determined according to the use, CODCr and SS indicators shall be as specified in Table 3.2.4, and other indicators shall comply with the provisions of current relevant national standards.



Table 3.2.4 CODCr and SS indicators of reused rainwater

Item indicator Replenishment of recirculated cooling system Ornamental water landscape Recreational water landscape Greening Vehicle flushing Road sprinkling Toilet flushing

CODcr(mg/L) ≤30 ≤30 ≤20 - ≤30 - ≤30

SS(mg/L) ≤5 ≤10 ≤5 ≤10 ≤5 ≤10 ≤10





3.2.5 When rainwater is used for multiple purposes at the same time, its water quality shall be determined according to the highest water quality standard.



3.2.6 The daily rainwater infiltration (utilization) amount of infiltration equipment shall be calculated using the following equation:



(3.2.6)



where,



Ws——the amount of infiltration, ｍ3;



α——the comprehensive safety coefficient, generally taken as 0.5~0.8;



K——the permeability coefficient of soil, ｍ/s;



J——the hydraulic gradient, generally taken as J=1.0;



As——the effective permeation area, m2;



ts——the infiltration duration, s, taken by 24 hours.



3.2.7 The permeability coefficient of soil shall be determined according to the measured data. It may be selected according to 3.2.7 if the measured data are not available.



 

Table 3.2.7 Permeability coefficient of soil

Stratum Stratigraphic particle size Permeability coefficient, K

Particle size (mm) Weight (%) (m/s) (m/h)

Clay <5.70× 10-8

Silty clay 5.70×10-8~1.16×10-6

Floury soil 1.16×10-6~5.79×10-6 0.0042~0.0208

Silt >0.075 >50 5.79×10-6~1.16×10-5 0.0208~0.0420

Fine sand >0.075 >85 1.16×10-5~5.79×10-5 0.0420~0.2080

Medium sand >0.25 >50 5.79×10-5~2.31×10-4 0.2080~0.8320

Homogeneous medium sand 4.05×10-4~5.79×10-4

Coarse sand >0.50 >50 2.31×10-4~5.79×10-4



3.2.8 The effective permeation area of the infiltration equipment shall be determined according to the following requirements:



1 The horizontal infiltration area is calculated according to the projected area;



2 The vertical infiltration area is calculated as 1/2 of the vertical area corresponding to the effective water level height;



3 The inclined infiltration area is calculated according to the actual area of the inclined surface corresponding to 1/2 of the effective water level height;



4 The top area of infiltration equipment buried underground is not included.



4 Rainwater management and utilization system



4.1 General requirements



4.1.1 Rainwater management and utilization system shall manage the total annual runoff and peak discharge runoff of perennial rainfall after the construction or reconstruction of the site to the level before construction and development, and shall comply with 3.1.2 and 3.1.3 of this code.



4.1.2 As for rainwater management and utilization, the following shall be adopted: a single system or a combination of multiple systems in rainwater infiltration system, harvesting and reuse system, detention and controlled drainage system, and the following provisions shall be followed:



1 The rainwater infiltration system shall consist of rainwater harvesting, storage and infiltration equipment;



2 The harvesting and reuse system shall be equipped with facilities such as rainwater harvesting, storage, treatment and reuse water pipe networks;



3 The detention and controlled drainage system shall be equipped with rainwater harvesting, regulating and detention equipment, discharge pipelines and other facilities.



4.1.3 The selection of rainwater management and utilization system shall meet the following requirements:



1 The permeability coefficient of soil of the infiltration system shall be between 10-6 m/s and 10-3 m/s, and the distance between the infiltration surface and the groundwater level shall be greater than 1.0 m, and the infiltration surface shall be calculated from the lowest point;



2 The harvesting and reuse system should be used in areas with average annual rainfall greater than 400 mm;



3 The detention and controlled drainage system should be used in places with flood control and drainage requirements or places where rainwater resource utilization is restricted.



4.1.4 The layout of rainwater management and utilization equipment shall meet the following requirements:



1 The site design and architectural layout shall be based on the current terrain and landforms, and the existing water bodies, wetlands, ponds, ditches, etc. within the site shall be protected and reasonably utilized;



2 The spatial layout of impervious surface and green spaces shall be optimized, and green spaces that can absorb runoff rainwater should be arranged around buildings, squares, and roads;



3 The vertical design of buildings, roads, green spaces, etc. shall be conducive to runoff flow into rainwater management and utilization equipment.



4.1.5 Rainwater infiltration sites shall have detailed geological survey data, which shall include the distribution of regional stagnant water layer, soil types and corresponding permeability coefficients, groundwater dynamics, etc.



4.1.6 Rainwater infiltration shall not cause geological disasters and damage buildings. Rainwater infiltration system shall not be used in the following places:



1 Places that may cause collapse and landslide disasters;



2 Places that cause harm to the living environment and natural environment;



3 Special soil geological sites such as self-weight collapsible loess, expansive soil and high saline soil.



4.1.7 Rainwater harvesting and reuse systems shall not be used for rainwater from infectious disease hospitals, rainwater from sites with serious surface pollution such as heavy metal pollution and chemical pollution. For buildings and sub-districts with special pollution sources, rainwater management and utilization projects shall be subject to special demonstration.



4.1.8 Construction land equipped with rainwater management and utilization system shall be equipped with rainwater drainage measures, and ground elevation control shall be carried out to prevent rainwater from outside the area from flowing into the land. The vertical planning and design of urban land shall comply with the requirements of the national professional standard CJJ 83 Code for vertical planning on urban and rural development land.



4.1.9 The rainwater management and utilization system shall not cause harm to the soil environment, underground aquifer water quality, public health and environmental sanitation, and shall be convenient for maintenance and management. The selection of plants in landscape shall meet the needs of rainwater management and utilization.



4.1.10 Low water quality standard water in the reused water supply pipe network shall not enter the high water quality standard water system.



4.1.11 Rainwater structures and pipelines shall comply with the current national standards GB 50069 Structural design code for special structures of water supply and waste water engineering and GB 50015 Standard for design of building water supply and drainage.

Foreword i
1 General provisions
2 Terms and symbols
2.1 Terms
2.2 Symbols
3 Water quantity and water quality
3.1 Rainfall and rainwater quality
3.2 Rainwater resource utilization and water quality
4 Rainwater management and utilization system
4.1 General requirements
4.2 System type selection
4.3 System equipment calculation
5 Rainwater harvesting and exclusion
5.1 Roof rainwater harvesting
5.2 Harvesting rainwater from impervious surface
5.3 Rainwater removal
5.4 Rainwater exclusion
6 Rainwater infiltration
6.1 General requirements
6.2 Infiltration equipment
7 Rainwater storage and reuse
7.1 General requirements
7.2 Storage equipment
7.3 Rainwater reuse water supply system
7.4 System control
8 Water treatment
8.1 Water treatment process
8.2 Treatment facilities
8.3 Rainwater treatment station
9 Detention and controlled drainage
10 Construction and acceptance
10.1 General requirements
10.2 Buried infiltration equipment
10.3 Permeable ground
10.4 Assembled combination pool
10.5 Pipe laying
10.6 Equipment installation
11 Completion acceptance
11.1 Hydrostatic test
11.2 Acceptance
12 Operation management
Annex A Rainfall data of the major cities in China
Explanation of wording in this code

1 总则
1.0.1为构建城镇源头雨水低影响开发系统，建设或修复水环境与生态环境，实现源头雨水的径流总量控制、径流峰值控制和径流污染控制，使建筑、小区与厂区的低影响开发雨水系统工程做到技术先进、经济合理、安全可靠，制定本规范。
1.0.2本规范适用于海绵型民用建筑与小区、工业建筑与厂区雨水控制及利用工程的规划、设计、施工、验收和运行管理。本规范不适用于雨水作为生活饮用水水源的雨水利用工程。
1.0.3雨水控制及利用工程应根据项目的具体情况、当地的水资源状况和经济发展水平合理采用低影响开发雨水系统的各项技术。
1.0.4雨水控制及利用工程可采用渗、滞、蓄、净、用、排等技术措施。
1.0.5规划和设计阶段文件应包括雨水控制及利用内容。雨水控制及利用设施应与项目主体工程同时规划设计，同时施工，同时使用。
1.0.6雨水控制及利用工程应采取确保人身安全、使用及维修安全的措施。
1.0.7雨水控制及利用工程应结合室外总平面、园林景观、建筑、给水排水等专业相互配合设计。
1.0.8建筑与小区雨水控制及利用工程的规划、设计、施工、验收和运行管理，除应符合本规范外，尚应符合国家现行有关标准的规定。






2 术语和符号
2.1 术语
2.1.1雨水控制及利用 rainwater manegement and utilization
径流总量、径流峰值、径流污染控制设施的总称，包括雨水入渗（渗透）、收集回用、调蓄排放等。
2.1.2年径流总量控制率volume capture ratio of annual rainfall
根据多年日降雨量统计分析计算，场地内累计全年得到控制的雨量占全年总降雨量的百分比。
2.1.4下垫面underlying surface
降雨受水面的总称。包括屋面、地面、水面等。
2.1.5土壤渗透系数permeability coefficient of soil
单位水力坡度下水的稳定渗透速度。
2.1.6雨量径流系数 pluviometric runoff coefficient
设定时间内降雨产生的径流总量与总雨量之比。
2.1.7硬化地面 impervious surface
通过人工行为使自然地面硬化形成的不透水地面。
2.1.8初期径流initial runoff
一场降雨初期产生一定厚度的降雨径流。
2.1.9弃流设施initial rainwater removal equipment
利用降雨量、雨水径流厚度控制初期径流排放量的设施。有自控弃流装置、渗透弃流装置、弃流池等。
2.1.10渗透弃流装置infiltration- removal well
具有一定贮存容积和截污功能，将初期径流渗透至地下的装置。
2.1.11渗透设施infiltration equipment
贮存雨水径流量并进行渗透的设施，包括渗透沟渠、入渗池、入渗井、透水铺装等。
2.1.12入渗池infiltration pool
雨水通过侧壁和池底进行入渗的埋地水池。
2.1.13入渗井infiltration well
雨水通过侧壁和井底进行入渗的设施。
2.1.14渗透管－排放系统infiltration-drainage pipe system
采用渗透检查井、渗透管将雨水有组织的渗入地下，超过渗透设计标准的雨水由管沟排放的系统。
2.1.15透水铺装pervious pavement
由透水面层、基层、底基层等构成的地面铺装结构，能储存、渗透自身承接的降雨。
2.1.16植被浅沟grass swale
在地表浅沟中种植植被，可以截留雨水并入渗、或转输雨水并利用植被净化雨水的设施。
2.1.17渗透管沟infiltration trench
具有渗透功能的雨水管或沟。
2.1.18渗透检查井infiltration manhole
具有渗透功能和一定沉砂容积的管道检查维护装置。
2.1.19集水渗透检查井collect-infiltration manhole
顶盖收集地面雨水、且具有渗透功能和一定沉砂容积的管道检查维护装置。
2.1.20雨水储存设施rainwater storage equipment
储存未经处理的雨水的设施。
2.1.21湿塘Wet pond
以雨水作为主要补水水源的具有雨水调蓄和净化功能的景观水体。
2.1.22调蓄排放设施detention and controlled drainage equipment
贮存一定时间的雨水，削减向下游排放的雨水洪峰径流量、延长排放时间的设施。
2.1.23生物滞留设施bioretention system, bioretention cell
通过植物、土壤和微生物系统滞蓄、渗滤、净化径流雨水的设施。

2.2 符号
2.2.1 流量、水量
Q——调蓄池进水流量；
Q ——出水管设计流量；
Qy——设施处理能力；
Vh——收集回用系统雨水储存设施的储水量；
VL——雨水控制及利用设施截留雨量；
VL1——渗透设施的截留雨量；
VL2——收集回用设施的截留雨量；
VL3——调蓄排放设施的截留雨量；
Vs——入渗系统的储存水量；
Vt——调蓄排放系统雨水储存设施的储水量；
W——需控制及利用的雨水径流总量；
W1——入渗设施汇水面上的雨水设计径流量；
W2——收集回用系统汇水面上的雨水设计径流量；
Wc——渗透设施进水量；
Ws——渗透量；
Wi——初期径流弃流量；
Wp——建设场地外排雨水总量；
Wx1——入渗设施内累积的雨水量达到最大值过程中渗透的雨水量；
Wy——回用系统的最高日用水量；
q——设计暴雨强度；
qc——渗透设施产流历时对应的暴雨强度；
qi——某类用水户的最高日用水定额。
2.2.2 水头损失、几何特征
As——有效渗透面积；
F——硬化汇水面面积；
F0——渗透设施的直接受水面积；
Fy——渗透设施受纳的汇水面积；
Fz——建设场地总面积；
hy——设计日降雨量；
hp——排水设计日降雨量；
δ——初期径流弃流厚度。
2.2.3 计算系数及其它
A、b、c、n——当地降雨参数；
J——水力坡降；
Ｋ——土壤渗透系数；
fk——建设场地雨水控制及利用率；
ni——某类用水户的户数；
α——综合安全系数；
Ψ0——控制径流峰值所对应的径流系数，应符合当地规划控制要求；
Ψc——雨量径流系数；
Ψz——建设场地综合雨量径流系数。
2.2.4 时间
P——设计重现期；
T——雨水处理设施的日运行时间；
t——降雨历时；
t1——汇水面汇水时间；
t2——管渠内雨水流行时间；
tc——渗透设施产流历时；
tm——调蓄池蓄水历时；
ts——渗透时间；
ty——用水时间。


3 水量与水质
3.1 降雨量和雨水水质
3.1.1降雨量应根据当地近期20年以上降雨量资料确定。当缺乏资料时可采用本规范附录A的数值。
3.1.2 建设用地内应对年雨水径流总量进行控制，控制率及相应的设计降雨量应符合当地海绵城市规划控制指标要求。
3.1.3建设用地内应对雨水径流峰值进行控制，需控制利用的雨水径流总量应按下式计算。当水文及降雨资料具备时，也可按多年降雨资料分析确定。
W =10（Ψc-Ψ0）hyF （3.1.3）
式中：W——需控制及利用的雨水径流总量（m3）；
Ψc——雨量径流系数；
Ψ0——控制径流峰值所对应的径流系数，应符合当地规划控制要求；
hy——设计日降雨量（mm）；
F ——硬化面汇水面积（hm2），应按硬化汇水面水平投影面积计算。
3.1.4雨量径流系数宜按表3.1.4采用，汇水面积的综合径流系数应按下垫面种类加权平均计算。
表3.1.4雨量径流系数
下垫面类型 雨量径流系数ψc
硬屋面、未铺石子的平屋面、沥青屋面 0.80～0.90
铺石子的平屋面 0.60～0.70
绿化屋面 0.30～0.40
混凝土和沥青路面 0.80～0.90
块石等铺砌路面 0.50～0.60
干砌砖、石及碎石路面 0.40
非铺砌的土路面 0.30
绿地 0.15
水面 1.00
地下建筑覆土绿地(覆土厚度≥500mm) 0.15
地下建筑覆土绿地(覆土厚度＜500mm) 0.30～0.40
透水铺装地面 0.29~0.36

3.1.5设计日降雨量应按常年最大24小时降雨量确定，可按本规范第3.1.1条的规定或按当地降雨资料确定，且不应小于当地年径流总量控制率所对应的设计降雨量。
3.1.6硬化汇水面面积应按硬化地面、非绿化屋面、水面的面积之和计算，并应扣减透水铺装地面面积。
3.1.7屋面雨水经初期径流弃流后的水质，宜根据当地实测资料确定。当无实测资料时，可采用下列经验值：CODCr 70 mg/L ~100mg/L；SS 20 mg/L ~40mg/L；色度 10度~40度。
3.1.8排入市政雨水管道的污染物总量宜进行控制。排入城市地表水体的雨水水质应满足该水体的水质要求。
3.2 雨水资源化利用量和水质
3.2.1绿化、道路及广场浇洒、车库地面冲洗、车辆冲洗、循环冷却水补水等的最高日用水量应按现行国家标准《建筑给水排水设计规范》GB 50015的规定执行，平均日用水量应按现行国家标准《民用建筑节水设计标准》GB50555的规定执行。
3.2.2各类建筑物最高日冲厕用水量应按现行国家标准《建筑中水设计规范》GB50336的规定执行。
3.2.3景观水体补水量应根据当地水面蒸发量和水体渗透量、水处理自用水量等因素综合确定。
3.2.4回用雨水集中供应系统的水质应根据用途确定，CODCr和SS指标应符合表3.2.4的规定，其余指标应符合国家现行相关标准的规定。
表3.2.4 回用雨水CODCr和SS指标
项目指标 循环冷却系统补水 观赏性
水景 娱乐性
水景 绿化 车辆
冲洗 道路
浇洒 冲厕
CODcr（mg/L）≤ 30 30 20 - 30 - 30
SS（mg/L）≤ 5 10 5 10 5 10 10

3.2.5当雨水同时用于多种用途时，其水质应按最高水质标准确定。
3.2.6渗透设施的日雨水渗透（利用）量应按下式计算：
（3.2.6）
式中：Ws——渗透量（ｍ3）；
α——综合安全系数，一般可取0.5～0.8；
K——土壤渗透系数（ｍ/s）；
J——水力坡降，一般可取Ｊ=1.0；
As——有效渗透面积（m2）；
ts——渗透时间（s），按24小时计。
3.2.7土壤渗透系数应根据实测资料确定。当无实测资料时，可按表3.2.7选用。
表3.2.7 土壤渗透系数
地层 地层粒径 渗透系数K
粒径（mm） 所占重量（%） （m/s） （m/h）
粘土 < 5.70×10-8
粉质粘土 5.70×10-8～1.16×10-6
粉土 1.16×10-6～5.79×10-6 0.0042～0.0208
粉砂 > 0.075 > 50 5.79×10-6～1.16×10-5 0.0208～0.0420
细砂 > 0.075 > 85 1.16×10-5～5.79×10-5 0.0420～0.2080
中砂 > 0.25 > 50 5.79×10-5～2.31×10-4 0.2080～0.8320
均质中砂 4.05×10-4～5.79×10-4
粗砂 > 0.50 > 50 2.31×10-4～5.79×10-4
3.2.8渗透设施的有效渗透面积应按下列要求确定：
1 水平渗透面按投影面积计算；
2 竖直渗透面按有效水位高度所对应的垂直面积的1/2计算；
3 斜渗透面按有效水位高度的1/2所对应的斜面实际面积计算；
4 埋入地下的渗透设施的顶面积不计。

4 雨水控制及利用系统设置
4.1 一般规定
4.1.1雨水控制及利用系统应使场地在建设或改建后，对于常年降雨的年径流总量和外排径流峰值的控制达到建设开发前的水平，并应符合本规范第3.1.2条和第3.1.3条的规定。
4.1.2雨水控制及利用应采用雨水入渗系统、收集回用系统、调蓄排放系统中的单一系统或多种系统组合，并应符合下列规定：
1 雨水入渗系统应由雨水收集、储存、入渗设施组成；
2 收集回用系统应设雨水收集、储存、处理和回用水管网等设施；
3 调蓄排放系统应设雨水收集、调蓄设施和排放管道等设施。
4.1.3雨水控制及利用系统的选用应符合下列规定：
1 入渗系统的土壤渗透系数应为10-6m/s~10-3m/s之间，且渗透面距地下水位应大于1.0m，渗透面应从最低处计；
2 收集回用系统宜用于年均降雨量大于400mm的地区；
3 调蓄排放系统宜用于有防洪排涝要求的场所或雨水资源化受条件限制的场所。
4.1.4雨水控制及利用设施的布置应符合下列规定：
1 应结合现状地形地貌进行场地设计与建筑布局，保护并合理利用场地内原有的水体、湿地、坑塘、沟渠等；
2应优化不透水硬化面与绿地空间布局，建筑、广场、道路周边宜布置可消纳径流雨水的绿地；
3 建筑、道路、绿地等竖向设计应有利于径流汇入雨水控制及利用设施。
4.1.5雨水入渗场所应有详细的地质勘察资料，地质勘察资料应包括区域滞水层分布、土壤种类和相应的渗透系数、地下水动态等。
4.1.6雨水入渗不应引起地质灾害及损害建筑物。下列场所不得采用雨水入渗系统：
1 可能造成坍塌、滑坡灾害的场所；
2 对居住环境以及自然环境造成危害的场所；
3 自重湿陷性黄土、膨胀土和高含盐土等特殊土壤地质场所。
4.1.7传染病医院的雨水、含有重金属污染和化学污染等地表污染严重的场地雨水不得采用雨水收集回用系统。有特殊污染源的建筑与小区，雨水控制及利用工程应经专题论证。
4.1.8设有雨水控制及利用系统的建设用地，应设有雨水外排措施，并应进行地面标高控制，防止区域外雨水流入用地，城市用地的竖向规划设计应符合国家行业标准《城市用地竖向规划规范》CJJ83的要求。
4.1.9雨水控制及利用系统不应对土壤环境、地下含水层水质、公众健康和环境卫生等造成危害，并应便于维护管理。园林景观的植物选择应适应雨水控制及利用需求。
4.1.10回用供水管网中低水质标准水不得进入高水质标准水系统。
4.1.11雨水构筑物及管道设置应符合现行国家标准《给水排水工程构筑物结构设计规范》GB50069和《建筑给水排水设计规范》GB50015的规定。
4.2 系统选型
4.2.1雨水控制及利用系统的型式和各系统控制及利用的雨水量，应根据工程项目特点经技术经济比较后确定。
4.2.2雨水控制及利用应优先采用入渗系统或（和）收集回用系统，当受条件限制或条件不具备时，应增设调蓄排放系统。
4.2.3硬化地面、屋面、水面上的雨水径流应控制及利用，并应符合下列规定：
1 硬化地面雨水宜采用雨水入渗或排入水体；
2 屋面雨水宜采用雨水入渗、收集回用、或二者相结合的方式；
3降落在水体上的雨水应就地储存。
4.2.4屋面雨水利用方式的选择应根据下列因素综合确定：
1 当地水资源情况；
2 室外土壤的入渗能力；
3 雨水的需求量和用水水质要求；
4 杂用水量和降雨量季节变化的吻合程度；
5 经济合理性。
4.2.5符合下列条件之一时，屋面雨水应优先采用收集回用系统：
1 降雨量分布较均匀的地区；
2 用水量与降雨量季节变化较吻合的建筑区或厂区；
3 降雨量充沛地区；
4屋面面积相对较大的建筑。
4.2.6雨水回用用途应根据收集量、回用量、随时间的变化规律以及卫生要求等因素综合考虑确定。雨水可用于景观用水、绿化用水、循环冷却系统补水、路面和地面冲洗用水、冲厕用水、汽车冲洗用水、消防用水等。
4.2.7同时设有收集回用系统和调蓄排放系统时，宜合用雨水储存设施。
4.2.8同时设有雨水回用和中水系统时，原水不应混合，出水可在清水池混合。
4.3 系统设施计算
4.3.1单一系统渗透设施的渗透能力不应小于汇水面需控制及利用的雨水径流总量，当不满足时，应增加入渗面积或加设其他雨水控制及利用系统。下凹绿地面积大于接纳的硬化汇水面面积时，可不进行渗透能力计算。入渗面积应按下式计算：
As= W/（ KJts） （4.3.1）

4.3.2渗透设施的渗透时间ts应按24h计，其中入渗池、井的渗透时间宜按3d计。
4.3.3入渗系统应设置雨水储存设施，单一系统储存容积应能蓄存入渗设施内产流历时的最大蓄积雨水量，并应按下式计算：
Vs=max(Wc- KJAstc) （4.3.3）
式中：Vs——入渗系统的储存水量（m3）；
Wc——渗透设施进水量（m3）。
4.3.4渗透设施进水量应按下式计算，且不宜大于按本规范式3.1.3计算的日雨水设计径流总量：
（4.3.4）
式中：Fy ——渗透设施受纳的汇水面积（hm2）；
F0 ——渗透设施的直接受水面积（hm2），埋地渗透设施为0；
tc ——渗透设施设计产流历时（min），不宜大于120min；
qc ——渗透设施设计产流历时对应的暴雨强度（L/s.hm2），按2年重现期计算。
4.3.5单一雨水回用系统的平均日设计用水量不应小于汇水面需控制及利用雨水径流总量的30%。当不满足时，应在储存设施中设置排水泵，其排水能力应在12h内排空雨水。
4.3.6雨水收集回用系统应设置储存设施，其储水量应按下式计算。当具有逐日用水量变化曲线资料时，也可根据逐日降雨量和逐日用水量经模拟计算确定。
Vh=W- Wi （4.3.6）
式中：Vh——收集回用系统雨水储存设施的储水量（m3）；
Wi——设计初期径流弃流量（m3），应根据本规范式5.3.5计算。
4.3.7雨水调蓄排放系统的储存设施出水管设计流量应符合下列规定：
1当降雨过程中排水时，应按下式计算：
Q'=Ψ0 q F （4.3.7）
式中：Q'——出水管设计流量（L/s）；
Ψ0——径流系数，宜取0.2；
q——暴雨强度（L/s.hm2），按2年重现期计算。
2当降雨过后才外排时，宜按6h~12h排空调蓄池计算。
4.3.8雨水调蓄排放系统的储存设施容积应符合下列规定：
1降雨过程中排水时，宜根据设计降雨过程变化曲线和设计出流量变化曲线经模拟计算确定，资料不足时可按下式计算：
(4.3.8）
式中：Vt——调蓄排放系统雨水储存设施的储水量（m3）；
tm——调蓄池设计蓄水历时（min），不大于120min；
Q——调蓄池进水流量（L/s）；
Q ——出水管设计流量（L/s），按本规范式4.3.7确定。
2 当雨后才排空时，应按汇水面雨水设计径流总量W取值。
4.3.9当雨水控制及利用采用入渗系统和收集回用系统的组合时，入渗量和雨水设计用量应按下列公式计算：
KJAsts+Σqinity=W (4.3.9-1）
KJAsts=W1 (4.3.9-2）
Σqinity =W2 (4.3.9-3）
式中：ts——渗透时间（s），按24h计；对于渗透池和渗透井，宜按3d计；
qi——第i种用水户的日用水定额（m3/d），根据现行国家标准《建筑给水排水设计规范》GB50015和《建筑中水设计规范》GB50336计算；
ni——第i种用水户的用户数量；
ty——用水时间，宜取2.5d；当雨水主要用于小区景观水体，并且作为该水体主要水源时，可取7d甚至更长时间，但需同时加大蓄水容积；
W1——入渗设施汇水面上的雨水设计径流量（m3）；
W2——收集回用系统汇水面上的雨水设计径流量（m3）。
4.3.10当雨水控制及利用采用多系统组合时，各系统的有效贮水量应按下式计算：
（Vs+Wx1）+Vh+ Vt=W (4.3.10）
式中：Wx1——入渗设施内累积的雨水量达到最大值过程中渗透的雨水量（m3）。
4.3.11建设场地日降雨控制及利用率应按下式计算：
fk = 1 - Wp /（10hpFz） （4.3.11）
式中：fk——建设场地日降雨控制及利用率；
Wp——建设场地外排雨水总量（m3）；
hp——日降雨量（mm），因重现期而异；
Fz——建设场地总面积（m2）。
4.3.12建设场地外排雨水总量应按下式计算：
Wp= 10ΨzhpFz–VL (4.3.12）
式中：Ψz——建设场地综合雨量径流系数，应按本规范第3.1.4条确定；
VL——雨水控制及利用设施截留雨量（m3）。
4.3.13雨水控制及利用系统的有效截留雨量应为各系统的截留雨量之和，并应按下式计算：
VL= VL1+ VL2+ VL3 （4.3.13）
式中：VL1——渗透设施的截留雨量（m3）；
VL2——收集回用系统的截留雨量（m3）；
VL3——调蓄排放设施的截留雨量（m3）。
4.3.14各雨水控制及利用系统或设施的有效截留雨量应通过水量平衡计算，并应根据下列影响因素为确定：
1 渗透系统或设施的主要影响因素应包括：有效储水容积、汇水面日径流量、日渗透量。当透水铺装按本规范表3.1.4取径流系数时，可不计算截留雨量。
2 收集回用系统的主要影响因素应包括：雨水蓄存设施的有效储水容积、汇水面日径流量、雨水用户的用水能力。
3 调蓄排放系统的主要影响因素应包括：调蓄设施的有效储水容积、汇水面日径流量。


5 雨水收集与排除
5.1 屋面雨水收集
5.1.1屋面应采用对雨水无污染或污染较小的材料，有条件时宜采用种植屋面。种植屋面应符合现行行业标准《种植屋面工程技术规程》JGJ 155的规定。
5.1.2屋面雨水系统中设有弃流设施时，弃流设施服务的各雨水斗至该装置的管道长度宜相同。
5.1.3屋面雨水宜采用断接方式排至地面雨水资源化利用生态设施。当排向建筑散水面进入下凹绿地时，散水面宜采取消能防冲刷措施。
5.1.4屋面雨水收集系统应独立设置，严禁与建筑生活污水、废水排水连接。严禁在民用建筑室内设置敞开式检查口或检查井。
5.1.5屋面雨水收集系统的布置应符合国家现行标准《建筑给水排水设计规范》GB50015和《建筑屋面雨水排水系统技术规程》CJJ 142的规定。
5.1.6屋面雨水收集管道汇入地下室内的雨水蓄水池、蓄水罐或弃流池时，应设置紧急关闭阀门和超越管向室外重力排水，紧急关闭阀门应由蓄水池水位控制，并能手动关闭。
5.1.7屋面雨水收集系统和雨水储存设施之间的室外输水管道，当设计重现期比上游管道的重现期小时，应在连接点设检查井或溢流设施。埋地输水管上应设检查口或检查井，间距宜为25m~40m。
5.1.8雨水收集回用系统均应设置弃流设施，雨水入渗收集系统宜设弃流设施。
5.1.9种植屋面上设置雨水斗时，雨水斗宜设置在屋面结构板上，斗上方设置带雨水箅子的雨水口，并应有防止种植土进入雨水斗的措施。
5.2 硬化地面雨水收集
5.2.1 建设用地内平面及竖向设计应考虑地面雨水收集要求，硬化地面雨水应有组织地重力排向收集设施。
5.2.2雨水口宜设在汇水面的低洼处，顶面标高宜低于地面10mm～20mm。
5.2.3雨水口担负的汇水面积不应超过其集水能力，且最大间距不宜超过40m。
5.2.4 雨水收集宜采用具有拦污截污功能的雨水口或雨水沟，且污物应便于清理。
5.2.5雨水收集系统中设有集中式雨水弃流时，各雨水口至容积式弃流装置的管道长度宜相同。
5.3 雨水弃流
5.3.1屋面雨水收集系统的弃流装置宜设于室外，当设在室内时，应为密闭型式。雨水弃流池宜靠近雨水蓄水池，当雨水蓄水池设在室外时，弃流池不应设在室内。
5.3.2屋面雨水收集系统宜采用容积式弃流装置。当弃流装置埋于地下时，宜采用渗透弃流装置。
5.3.3地面雨水收集系统宜采用渗透弃流井或弃流池。分散设置的弃流设施，其汇水面积应根据弃流能力确定。
5.3.4初期径流弃流量应按下垫面实测收集雨水的CODCr、SS、色度等污染物浓度确定。当无资料时，屋面弃流径流厚度可采用2mm～3mm，地面弃流可采用3mm～5mm。
5.3.5初期径流弃流量应按下式计算：
Wi＝ （5.3.5）
式中：Wi——初期径流弃流量（m3）；
δ——初期径流弃流厚度（mm）。
5.3.6弃流装置及其设置应便于清洗和运行管理。弃流装置应能自动控制弃流。
5.3.7截流的初期径流宜排入绿地等地表生态入渗设施，也可就地入渗。当雨水弃流排入污水管道时，应确保污水不倒灌至弃流装置内和后续雨水不进入污水管道。
5.3.8当采用初期径流弃流池时，应符合下列规定：
1 截流的初期径流雨水宜通过自流排除；
2 当弃流雨水采用水泵排水时，池内应设置将弃流雨水与后期雨水隔离的分隔装置；
3 应具有不小于0.10的底坡，并坡向集泥坑；
4 雨水进水口应设置格栅，格栅的设置应便于清理并不得影响雨水进水口通水能力；
5 排除初期径流水泵的阀门应设置在弃流池外；
6 宜在入口处设置可调节监测连续两场降雨间隔时间的雨停监测装置，并与自动控制系统联动；
7 应设有水位监测措施；
8 采用水泵排水的弃流池内应设置搅拌冲洗系统。
5.3.9渗透弃流井应符合下列规定：
1井体和填料层有效容积之和不应小于初期径流弃流量；
2 井外壁距建筑物基础净距不宜小于3m；
3渗透排空时间不宜超过24h。
5.4 雨水排除
5.4.1排水系统应对雨水控制及利用设施的溢流雨水进行收集、排除。
5.4.2当绿地标高低于道路标高时，路面雨水应引入绿地，雨水口宜设在道路两边的绿地内，其顶面标高应高于绿地20mm～50mm，且不应高于路面。
5.4.3雨水口宜采用平箅式，设置间距应根据汇水面积确定，且不宜大于40m。
5.4.4透水铺装地面的雨水排水设施宜采用排水沟。
5.4.5渗透管－排放系统应满足排除雨水流量的要求，管道水力计算可采用有压流。
5.4.6 雨水排除系统的出水口不宜采用淹没出流。
5.4.7室外下沉式广场、局部下沉式庭院，当与建筑连通时，其雨水排水系统应采用加压提升排放系统；当与建筑物不连通且下沉深度小于1m时，可采用重力排放系统，并应确保排水出口为自由出流。处于山地或坡地且不会雨水倒灌时，可采用重力排放系统。
5.4.8与市政管网连接的雨水检查井应满足雨水流量测试要求。
5.4.9外排雨水管道的水力计算应符合现行国家标准《建筑给水排水设计规范》GB50015的规定。