Table 1.
Division by area. Author’s study
| Group type | Housing estate | Research area [m2] | The presence of an underground car park |
|---|---|---|---|
| large | Wolne Miasto | 68 612 | yes |
| Nowe Żerniki | 73 642 | yes | |
| 19 dzielnica | 60 975 | yes | |
| Żoliborz Artystyczny | 84 000 | yes | |
| medium | Zielony Południk | 39 007 | no |
| Nadmorski Dwór | 33 958 | yes | |
| Idea | 36 614 | yes | |
| Beauforta | 47 752 | yes | |
| small | Sokółki Zielenisz | 18 948 | yes |
| Mickiewicza | 27 925 | yes | |
| Jaśminowy Mokotów | 24 952 | yes |
Figure 1.
The rainwater management system diagram on which the methodology is based. Author’s study
Figure 2.
(a) Zielony Południk, Gdańsk. Example of the carefully planned catchment of rainwater from the surface runoff; (b) Wolne Miasto, Gdańsk. Example of a design with untapped surface runoff potential. Author’s photos
Figure 3.
Percentage of the land cover of investigated estates. Author’s study
Figure 4.
Green area division. Author’s study
Table 2.
The quality of green areas. Author’s study
| Housing estate | Percentage of green area in total | Level of low grass | Level of greenery above 1m in height | Level of | Quality of green area |
|---|---|---|---|---|---|
| Wolne Miasto | 49% | high | medium | low | medium |
| Zielony Południk | 53% | low | high | medium | high |
| Nadmorski Dwór | 55% | high | medium | medium | medium |
| Idea | 56% | low | high | low | high |
| Beauforta | 46% | low | high | low | high |
| Sokółki Zielenisz | 45% | low | high | medium | high |
| Nowe Żerniki | 21% | high | medium | medium | medium |
| Mickiewicza | 70% | high | medium | - | medium |
| Jaśminowy Mokotów | 46% | low | low | high | low |
| 19 dzielnica | 30% | low | high | high | medium |
| Żoliborz Artystyczny | 49% | medium | low | high | low |
Table 3.
Terrain profile and its impact on RMS design. Terrain profiles are generated from geoportal.gov.pl. Author’s study
| Housing estate | Terrain profile | Description | Characteristic |
|---|---|---|---|
| Wolne Miasto |  | The section done across the plot (from the north to the south). a: 15.19 m | The topography of the area has great potential in shaping efficient RMS based on gravity water flow. |
| Zielony Południk |  | The section done along the lot (from the north-west to the south-east) a: 15 m | The topography of the area took a prime part in the shape of RMS at the estate. The areas placed lower are used as surface retention elements such as major rain gardens. |
| Nadmorski Dwór |  | The section done along the plot (from the north-west to the south-east) a: 1.93 m |
|
| Idea |  | The section done along the plot (from the west to the east) a: 0.65 m | The depression visible on the terrain profile was not visible on the side. The area was mostly flat and water flow was determined by slight infliction of the pavement. |
| Beauforta |  | The section done along the plot (from the north-west to the south-east) a: 1 m | The first depression was the emergency reservoir, and the second depression (drop 1m) was not visible on the side. The characteristics were drops in the place of the car park and rises in the place of buildings and inner courtyards. |
| Sokółki Zielenisz |  | The section done along the plot (from the south-west to the north-east) a: 1.85 m | The topography has good potential for shaping RMS, which was noticed and used for open channels. |
| Nowe Żerniki |  | The section done along the bottom part (from the west to the east) a: 4.88 m |
|
 | The section done along the middle part (from the west to the east) a: 0.98 m | ||
 | The section done along the upper part (from the west to the east) a: 2.98 m | ||
| Mickiewicza |  | The section done along the plot (from the west to the east) d: 1.7 m | That difference in height shown on the profile can be observed on the side as a slight depression with greenery. |
| Jaśminowy Mokotów |  | The section done along the plot (from the south-west to the north-east) d: 2.31 m | The visible height difference was in the area of private gardens. During inventory there was no observed significant height differences. |
| 19 dzielnica |  | The section done along the plot (from the north-west to the south-east) d: 4.39 m | The characteristics were high slopes in the inner courtyards that are accessible just for residents. |
| Żoliborz Artystyczny |  | The section done along the plot (from the east to the west) a: 7.7m | Except for one bigger drop (that is rather a hole, in its shape difficult to use as an RMS element) the area was moderately hilly and had a good potential for shaping RMS. |
Figure 5.
Elements directing the rainwater from the area above the car park to the permeable areas at housing estate Beauforta in Gdynia. (a) open channels; (b) pipes. Photos Author’s
Figure 6.
Examples of open channels directing the rainwater to the sumps (a) Wolne Miasto, Gdynia; (b) Sokółki Zielenisz, Gdynia. Photos Author’s
Figure 7.
NbS for infiltration (a) Idea estate, (b) Nowe Żerniki estate; NbS for temporary retention (c) Zielony Południk estate, (d) Zielony Południk estate; NbS for long-term retention (e) Beauforta estate, (f) Wolne Miasto estate. Photos Author’s
Table 4.
Summary table of elements of the rainwater management system. Author’s study
[i] x – not properly/intentionally implemented solution
Figure 8.
Typically, missing elements. Author’s study
Figure 9.
Diagram of RMS including typically missing elements. Author’s study